I'm sorry that you're going through that. I have a friend who was raised Jehovah's Witness and left. He also dated a non-JW as a teen, and it was partly due to his JW families intolerance and aggression in response that he decided to leave, despite the threat of being shunned. Now, he and his father are both outside of the religion, but his mother and sisters are still in it. It sucks, and sometimes he still tries to see if he can get through to talk to his siblings again, but his mom always blocks him from doing so. Despite this, he has a great relationship with his dad, and is constantly connecting with all sorts of different people, seeking his own truth and being kind in the ways he feels truly make sense. It's clear that having to break away from family like that was hard, but for him it was worth it.
I can't tell you what might be right for you, but I do want you to know that beyond those next few years, however trapped you may feel now, something better might be waiting.