Boyfriend being unfair?

So my bf and i have been together for over a year. Recently he's been borrowing a lot of money from me. I make 350 a month while he makes 900. He doesn't pay rent so he only needs it for gas to get to work 2 to 3 days a week. He borrowed 110 this month. The first time he was supposed to pay me back he got a small paycheck so he didn't want to. Now his paycheck is 500 and he says he won't give me more than 60, and give me 50 on his next paycheck. He won't pay everything back to me but buys weed and cigarettes. Am i overreacting?