Feeling like a roommate with benefits :(

My bf and I have been living together for almost five months and just recently got a place all to ourselves. We both have fulltime jobs and he goes to college. We don't spend much time together and when we do we argue. Our nights together always start well but when it comes to sex, he acts like its my job to give him a bj or initiate everything becuz he's too tired or stressed. When I suggest we makeout or ask him to initiate, he says I'm being childish or too needy. It's killing my confidence and our relationship. I feel rejected and like my sex drive is too high. And it sucks because when I do RARELY get to have sex with him, it's so amazing. I'm 18, I shouldn't be feeling like I'm in a rut. Someone give me advice please.