I may or may not be Si but I'm tired all the time basically, pretty much like you describe. I just think its because I'm forced to do boring shit. Every once in a while I get super excited and stay up for long periods and my attention is rivetted on something. At those times I'm not tired. But they're like rare treats. I'm not sure if tired is the right word, because I feel like it somehow doesn't do it justice, but even right now I'm fighting off taking a nap. I don't feel like tired in the sense that life isn't worth living or something, its more that sleeping feels like a valuable use of my time right now