This is normal and goes to prove how effective mind control is. Even when you know intellectually that there is no reason to be afraid, a part of your brain is not convinced. We all have a primitive part of our brain that controls the fight or flight syndrome. It responds very quickly in the event of a perceived threat. It's like when you suddenly see a rubber snake. The primitive part of your brain sees something alarming and your adrenaline starts flowing, your heart speeds up and you start moving. After a few seconds your normal, logical brain kicks in and says, wait a minute, that's not real, but it's a bit too late.
I believe this mechanism is responsible for most road rage incidents, and also is a factor in OCD type behavior. I also speculate it is what's in play when you are afraid to do things that were once considered forbidden by the cult. Your logical brain knows it's nonsense, but your primitive brain is still reacting to the JW conditioning and saying "Danger! Danger! Don't do that!". It really brings home how effective mind control can be. It will eventually go away since you aren't going to meetings anymore, but I bet you could speed up the process by deliberately doing things that were forbidden by the JWs. Start with little things, like listening to Christmas music, watch a Christmas movie, go to a party, etc. Gradually you will associate Christmas with pleasant memories, not JW paranoia.
When people have OCD type disorders they can be managed by gradually but consistently exposing people to what they fear, while helping people to manage the anxiety that is aroused by their OCD. Hoarding is an OCD type behavior, I saw an example where a young man had the idea that getting rid of the dog hair on his stairs would somehow hurt his dog. He knew that was not logical, but the OCD over rode his logical brain and caused severe anxiety, he couldn't get rid of the idea. With help he was able to retrain his brain to overcome the fear.
I think this one reason why people struggle with leaving the religion. They think they can just leave and move on, but they get all these uncomfortable feelings when trying to live a normal life. If they haven't learned the ttatt, they incorrectly interpret this anxiety as being God's way of telling them they should go back, the primitive part of the brain is connected with emotion also, the emotions take over. They are being manipulated months and even after years of leaving. It is also why trying to get someone to see ttatt doesn't work. Their fear of apostasy is aroused and they shut down and can't take in what you are saying.