relationship advice plzzz

I think he doesn't care anymore. Honestly, I kinda miss how things were before, as friends. And this is some sort of fear I've always had when I like someone, is that I might not be able to be completly open to them in fear of losing them (especially now in an official relationship) or that they distance themselves due to the same. In fact, although I worry about him a lot, he is colder than before or straight up ignoring, and although I try my best, things don't seem to be improving. I'll keep my cool but I do feel that maybe I believed too much.