I'm only 19 but I have a lowered sex drive?

Okay so sorry if this is too much information but i'm only 19 and I've usually (for as long as i can remember) been a pretty horny person. My boyfriend and I had a great sex life, we would have sex everytime we saw each other, sometime's twice a night and I would masturbate frequently too. We've been fighting a little bit recently, well not really fighting but we've kind of had an ongoing problem with talking, he works at 8 every morning so obviously he doesn't want to stay up and talk when he has to be up early but then whenever we have the chance it seems like something else always gets in the way, both of us are upset about this but i think it's bothering me more then him. Over all we're pretty good, we're not going to break up or anything but that upsets me a lot, w.e. we're working through it but now we have a bigger problem, I randomly just don't feel like having sex or really being intimate anymore. I mean we're always cuddly but now we only have sex like once a month and I only do it because I don't want him unsatisfied because he is very patient. I don't know whats wrong with me, I want to go back to the way i was :( what's going on?