That happens to me more often than I'd like it to. It could be a sign of depression for some people. For instance, I don't spend most of my day sad. I put on appearances at work and while I'm with family/friends. Even at work I'll have depressing thoughts, but I keep it inside as much as I can. Once the day comes to a close and I'm just in bed with my thoughts, then I start feeling sad, hopeless, and lonely. That's usually when I get on 7Cups haha. Seeing what everyone is going through reminds me that I'm not alone and that it could be worse. But yeah, once you wake up, then you don't feel as sad usually. I hope things improve for you and your nights become more zen.
Best wishes, Cain