I just want to start by saying you didn't do anything wrong, and you have nothing to feel ashamed of. Don't let these people judge you for doing something normal and healthy with your boyfriend.
That being said, there's nothing worse than being forced against your will to participate in a faith you find harsh and judgmental. Leave as soon as you can. Keep saving money and move in with your boyfriend when you're ready. And I would encourage you not to let the congregation or your parents know of these plans.