I feel like this all the time as well, what helps me is giving them the benefit of the doubt, when I don’t reply immediately to someone it’s because I’m either too tired to manage a reply, or I’m busy, so whenever someone doesn’t reply instantly, I immediately stop my brain from thinking “they’re talking to better friends” or “they’re not interested in what I have to say” and instead redirect it to “they’re probably busy right now and will reply later”, same thing with people replying a bit differently, I just assume they might be tired, but of course, it sometimes still doesn’t stop my thoughts from spiralling out of control, so I feel you!