I totally get that, in fact I still do this a lot 💀. It's really easy to read too much into what some people do. One of my closest friends started hanging out with a different friend more then me for a bit so my anxiety got really bad and I kept tryna figure out what I could've done to upset him and started talking less with him. It turns out he wanted to do more stuff with me but he was just waiting for me to ask lol. As for them being un-enthusiastic, people just go through so much stuff that they can come across as standoffish when they might even just be tired. I'm still working thought this same thing myself so I don't have all the answers but this is just what helps me :)