Please read and give advice?

So I’ve been talking to this guy since like 1.5 yr ago, and I like him alot I have real feelings for him and for a long time I think he did too, idk why we never made it official, that must have been my mistake. But lately he’s been different with me, he still talks to me every day and whatnot but he doesn’t compliment me as much, or reassure me that he likes me. He used to reply fast, and ask me to facetime but now idk he changed or maybe its just me? Am I just overthinking it?