Hello wayoutthere,
(firstly I want to point out that these are just my observations, not a therapists so I may be wrong.)
The panic attack and the mini breakdown you're having seems to be about a few things but firstly I would say control. You lost control over who knows your past and because it was let out without you knowing and it came out of the blue after such a long time, it's knocked you off your feet. So, from what you wrote, I would root this need for control about your past back to the first paragraph you wrote about the general feeling of not being able to control your own life as a young JW. This is a feeling a lot of born-ins have to deal with. I was one.
Also, another thing to contemplate is this, did you whilst a young JW, develop one personality for the kingdom hall and one personality for your outside life? This is very important. I ask because this is also a natural reaction that young JW's have to deal with. The problem with it is this, you develop one personality for the hall and try to fit in but you don't because you've got nothing in common with these people as you don't really get it or believe it (or you do love it but still...) that's the hall persona and so, you develop another persona for school and try to fit in there but because you try to keep your JW life secret and therefore can't talk about it freely because of shame, you don't fit in fully with them either and then because you're trying to develop friends at school and you don't want your parents to know this or that you don't love the hall, you develop another persona for home. Now you have three personas, all of them have secrets that they keep and all of them tell lies in order to not be found out. This in itself instills feelings of self loathing, dishonesty, unworthiness and loneliness/isolation. We learn to do this as a child but whereas adults, when doing it, do it knowing that it's just a persona that they switch back and forth from by choice, the child doesn't recognise it as a choice or something seperate or fake but instead thinks all three are what makes him/her a person. It's normal. So, this is hidden from themselves - they are unaware that they are doing it. Dangerous huh?!
So, time moves on and then you leave home and up til now, what you've learned is that in order to TRY and fit in because now you've confirmed to yourself that you don't fit in anywhere, you have to create a persona or personality that you think will be accepted by others. So in your situation, you've met your partner and at some point of trust decided to let that person in so far as you are able to but in order to make friends and forget your past, you make another persona. One that doesn't have any use for the old personas you first had and so you cut out one of your old personas or maybe two of them or three of them but now you're fostering new ones, ones for your kids,one for your parents as an out JW, ones for workmates... you see the point I'm making.
This I believe can be your problem and the feeling of never fitting in is because you've never tried to fit in AS YOU THE WHOLE YOU. Bits have been left out. It's left you feeling not a whole person inside maybe, how can you? You've cut some of you off. I say this because I've been through this and it may help you. Keeping this whole process together requires control - remembering what to say to the right people at the right time. You learn how to say what people want to hear and before long you forget who you are as a whole because you are some bits but not others and theres some bits missing, hidden. And then one day when you least expect it, casually, the rug gets pulled and the shock of knowing that people know about one of your old personalities makes you feel deep inside like a fraud, and not good enough and judged again and not in control and exhausted looking over all the effort you put into not being the real you and you fall into a pit and turn the lights off while you process. You lock yourself away due to fear, humiliation a sense of hopelessness and confusion but why does this happen? Well in my understanding it's because you felt traumatised by suddenly being confronted by your old, lost personality that someone essentially hung infront of your eyes and asked ''was this a part of you?''. Now, in the shock, your brain scrambles for reactions. Deny it it says as it tries to tell you, NO, you are not this person, we don't know this person it's just someone we had to be but it died, we killed it. But of course you know you can't lie to yourself. You know the real truth. You have to accept it. And when you look at that old persona and try to figure out what to do with it because you don't want it back you fall into unknown territory by becoming that old personality again for a time whilst in that pit. In extreme cases of this people can be known to revert to their childlike voice and actually believe that they are back in that time of when they felt like this, at the time of the trauma. You see this trait in abused children a lot. You didn't mention that you were abused but you are having a pretty strong reaction to your past.
So, the next question is why do you need to feel in control at all about your past and people knowing now that you're an adult. Well, I want to ask you a question. You said you left at 16 and never looked back but do you now know the TRUTH about the TRUTH? I mean you do know the religion is a false religion right? Inside are you 100% sure that it's a load of crap? Or don't you know fully? Because I'm wondering if when you tie yourself back to your old JW personality, if you're tying yourself back to fear and guilt and dread? The threat of Armageddon and you not surviving it? If this is so, immediately go to JWfacts and learn that this religion is a cult and 100% a pile of crap. I've found that it's only when you know it for sure, you can start to not feel frightened of your old selves and start putting ALL of the pieces that make you complete, back together.
Another reason why I ask if you know the TRUTH about the truth (TTATT) is because if you do, you should understand that the Watchtower cult use drip-fed, mind control techniques to manipulate members into the cult and remain in the cult. Your parents would have undergone this. We all did, even if you didn't believe it, it still affects you. You were told that you're a sinner, a speck of dust, a nothing. So to say you blame nothing on the GB and everything on your parents is very harsh, no? Please read or watch a youtube clip about this cult mind control techniques, it is very real and Watchtower use all of the weapons.
I went to a therapist but had to leave as it just wasn't for me. But it may help you as others have suggested.
I hope some of this was useful. Sorry for the longwinded post but the truth is, there's a healing in getting these things off your chest when you've experienced them yourself so, what I'm trying to say is, it helped me in writing this and I hope it helped you or maybe someone else who reads it if not. But anyway, good luck to you and if you want to PM me, feel free. Whatever you do, do not block this out and carry on. Deal with it, write everything down, research about questions you have and get it fixed. If you do see a therapist, write everyhting down before you go. It helps focus and doesn't enable anything to be left out. Whatever you do, don't be frightened of what's happening, it's your brain making new connections so guide it by teaching it what it needs to know in order to get the job done asap.
Lots of love x