The best way to stop the JW guilt thoughts is to get away from the cult. Meetings pump your head full of those thoughts and feelings.
You can make it all go away today. Well, not all, but a lot of it. Stop going. Accept your fate. Realize that your parents are toxic cult victims and let them go. If they are the only reason you're in, then maybe you need to come to terms with the fact that their love is conditional.
You can't have everything. Trying to is ultimately leaving you with nothing. You know you have to leave the cult. When are you going to do it for yourself? Only you can answer that. The sooner you do, at least by fading, the sooner you regain sanity. You can't find a way to live an unhealthy life and be healthy though.