feel like there isn’t a way out.

Is there someone you can stay with? Your parents or a friend? I'm sorry to say this, but if he loved you, he wouldn't think about using you this way. And the fact that he was willing to force you after saying no, only enforces it even more.
This may not be what you want to hear, but you need to. Get out. Call the cops, whatever you need to do to save yourself. Don't let him drag you down with him and his problems, he got himself in this mess. It's not your problem to help getting him out, especially not after the way he treated you. You deserve so much better than this, weather you think so or not.
And if you don't feel like you can do it on your own, tell someone, a friend or a family member, or anyone. Have them come with you and pack your things, and take you out of there. You are of no help to him in this state. It's the best thing you can do for yourself, and him, to get out. Make your health and wellbeing the first priority. Perhaps later, when you've found your way back, you can help him to if that's what you want.
Leaving is the hardest thing in the world, until you do it and then it's the easiest thing there ever was.

Okay, your relationship with this guy is not heathy. Is there anywhere you can go to get away from this? I know you want to help, but it's his mess. If he was really desperate, he would sleep with people for money. You should never have to put up with that. It will be hard, but please get away from him. Just completely remove yourself from this situation.

Thats the thing, hes all I have, I don't know my dad and my mum wants nothing to do with me, and i know people would say I should still tell her because she'd care, but honestly she wouldn't. And since I quit school for him a few years ago, I just ended up not speaking to my friends anymore. I feel like hes so stressed out about this whole thing and I do want to help, and be a better girlfriend but its just so hard. I feel like im never good enough, and this situation is so draining. Im scared about what will happen if I leave, because ive tried before, and it didn't end well. And he says things about what would happen if I tried again. Id have nowhere to go, and i feel like it could make things so much worse.

What your 'boyfriend' is doing is extremely wrong. This doesn't sound like a healthy relationship at all. He is using you. Remember that it is your body, your mind, and your life. Please try and get help: you don't deserve any of this, and please, please remember that. This situation could be dangerous and the sooner you get out the better- I would say that calling the police is your best option. Stay strong, don't let him make you suffer any more, and remember that you have the rights to your own body and mind.