Attraction issues?

Stephanie
So I've known my current bf since 10th grade. We recently started dating, long distance because I go to college out of state. Now, I have always had feelings for him and loved him over the years even when we drifted apart for some time. He has gained a little weight but it's not too noticeable. Lately I've been feeling like I'm not that attracted to him, I don't know if it's necessarily the way he looks or just how he acts idk. Like he just showed me his dick on FaceTime (of course I've seen it numerous times) but I wasn't really turned on at all. It's almost like he's turning into an old man and I'm nearly grossed out. Btw I'm 19 and he's 22. Has anyone felt like this before ? Lol help.