Boyfriend

So my boyfriend and I have been dating for 8 months. It's been rough and we got close to breaking up but he convinced me to give him one more chance. (He rights with me and yells at me 24/7 but since we said that he's stopped a bit) and well I feel like he doesn't actually wanna be with me. I got shown his Facebook messages and he was just saying how we are 'back together' but we never even broke up? So I don't know what that's about. And his mate Chris was saying he will get him a root for his birthday (in 2 days) and he said nah we will see (because Chris thought we broke up) or something like that and Chris said something like stick phat to ya girl aye and he was like yeah gotta get a few more roots first. 
I feel like I'm being used and I feel so worthless. I don't know what to do :( I can't lag his friend for showing me the messages so he can't know I saw or know about them. What do I do :(
His birthday is in 2 days and I'm buying him shoes for quite a bit of money and he was just talking about how pumped he is to get the shoes and that I'm getting them for him. 
I get the feels he will break up with me after his birthday and before mine next month. I honestly don't even want anything but it's how I feel, he will dump me so he doesn't have to get me anything. Or he will stay with me so he can get sex 🙄 which I won't be giving him. Thoughts?