I don't think anything's wrong with you. In fact, I think you're taking all this way better than most anyone I know if they were in your situation. I don't want to say "I know how you feel" because I've never experienced this situation specifically, but I know what it feels like to feel trapped and to feel like your life is just falling apart at the seams. For the longest time I tried to deal with it alone because I thought I had to, that no one could understand or even want to listen to me. But I have a friend now that I tell everything to. We have no secrets from each other, and it feels SO good to know I have someone to turn to whenever I need to talk about anything. I wholeheartedly urge you to find someone like that in your life, someone you can tell EVERYTHING to. It only needs to be one person, but you'll feel a lot better and you'll feel like you have a lifeline to grab on to when it feels like you're drowning. You've got us, the BP.net community as well! The members on here are just THE best people I've ever met on the internet. We'll listen whenever you need to vent, need support, or need advice!
Nobody's strong enough to do it alone. We all need someone there for us. Even if you don't feel like you can tell anyone right now, I'm sure you can ask your boyfriend for some extra love and attention when you're feeling alone. I'm sure that even if you can't tell him all the details, sometimes just being held by the person you care about makes you feel less alone and sad.
I know you can make it through though. You're stronger than you know.