Never in the mood

I am absolutely never in the mood/ want to have sex. I really feel like it’s putting a strain on my relationship. My boyfriend always wants to do something and I just always said no I’m not in the mood. Then we we do have sex I never enjoy it, it’s like okay let’s get this over with. We don’t live together and between work and college we hardly see each other. Sometimes I forget I’m in a relationship. People have told me that I am stressed and worried person and that could contribute to it. I honestly have no clue what to do and just talking about sex and all this makes me feel uncomfortable. I really have no clue what to do.

(I am not on birth control or any other day medications)