Decreased sex drive

Hi guys I used to have a very very high sex drive, like used to be hornier than my boyfriend and pretty much would be down for sex at any point. Lately I have wanted absolutely nothing to do with it. Nothing has happened, I'm so happy w my boyfriend, not on my period. Nothing. But it's to the point where even my boyfriend putting his head near my neck makes me cringe. It's so upsetting because it hurts him too snd makes us both cranky. My boyfriend is literally one of he most attractive people I know and I just don't get it. I've had my nexplanon implant for just over 2 years now and I'm wondering if maybe the waning hormones could be playing a role? Or just the hormone changes in general? Any advice?