Low sex drive

Like 30% of the time my sex drive is on 10 and the other 70% is just non existent and I don’t know why. My bf wants sex and I feel like I’m rejecting him but the one time I did try to just thug it out and do it when I didn’t feel like it I just laid there like a dead dog and it was not on purpose. It makes me want to cry because I don’t want him to feel like I only give him “pitty sex”. I enjoy our sex when we do have it I just don’t know why I don’t crave it a lot if at all. I could literally go a month without sex and not notice or care.... is there anything I could try that would boost my sex drive? Is it subconsciously him or me?