Decreased drive?

When my boyfriend and I first got together we had sex all the time, almost everyday for nearly a year and a half. I had a slow decline and then kind of just a drop off. I still think he’s extremely attractive and love him nothing has changed other than my drive. I’ve been on birth control since I basically started at 15 due to cycling issues so, that hasn’t changed either, (22 now) but I’m just never in the mood anymore. Nothing turns me on and I don’t even have the desire to masturbate anymore. Nothing really puts me in the mood unless we spend a long time trying and a lot of foreplay. It just gets tiring and seems more like a chore. What’s happening???? Any tips?