I'm trying to sit here and do computer work and my brain just and concentrate. It's like when you're really tired and your brain starts wandering into dreams except its every time I sit down. It's like I'm trying to read the screen and then there's a totally different conversation in my brain so I have to stop and try to focus. But it happens again and again. I feel like I'm going crazy. Sleep might help a bit but it'll be just as bad later or tomorrow. What's wrong with me?