Low sex drive at 19?

My boyfriend and I have been together for almost two years. He is a very sexual person and wants to have sex literally every day. I USED to be a sexual person, but I'm not anymore I guess. I probably only even think about sex once, maybe twice a week. I don't really ever just crave it. Sometimes, when I know my boyfriend is trying to get something going, I feel more annoyed than turned on and sometimes I think of it as being a hassle. I love my boyfriend and of course I am attracted to him. It's been like this for awhile and I just have never figured out what to do about it, because of course I don't want him to feel like this is a one sided deal (even though it is). Advice??