I was just noticing recently, I think my life is great, or just normal until I slowly start to realize that things aren't going the way I want them to (usually do to lack of movement throughout too many days in a row). Then I start to get depressed, but I continue to act however I was acting before, just slightly more likely to gnash out at someone. But recently I realized that when I'm really truly sleep deprived, I WILL notice how I ACTUALLY feel. When I'm really tired and really happy, I'll be bubbly and I'll have a hard time shutting up (possibly) or else I'll be really happy and really spacey but everyone will ask me if I'm sad because I'm too tired to make a facial expression. If I'm really upset then I'll cry really easily, everything will suddenly make sense, and I'll just want to be alone all day. If I'm angry inside it just switches to sad mode because being angry takes a lot of effort, and I don't see the point in putting effort into that anyway. If I'm just content because nothing is really on my mind, then I'll just daydream so something will be on my mind.
Personally, I find this phenomenon kind of intriguing. Apparently if I'm confused as to how I feel, I can just sleep deprive myself (yes, this can happen sometimes, because even if I explore how I feel, I usually come up with multiple possibilities. I have too many things on my mind to really pick out one emotion).
I will add, to those of you who may be worried, I do not think the consequences of lacking sleep are worth knowing exactly how I feel, and I probably will not go out of my way to try it. Just thought I'd add that.
Moving on, I think I might study neural pathways and such next time I research so that I can explain this. There is a high possibility that I am just weird. It also might just be that when I'm tired I can't keep my emotions in check, and when I'm not tired, I always have my guard up. Mind you, I have to have had less than 4 hours of sleep in the last thirty or so hours for me to be that tired. I think it can happen at 6, if on previous nights I also haven't had enough sleep. But it does take an extreme form. As soon as I have this topic ironed out, I will briefly inform you, if possible. If not, you'll get a good science lesson.
This is how I feel when I'm tired. Strange things go through my head, and I will think up things I'd normally only think to say in a dream. This is a very weird drawing. Quite reminiscent of my weird dreams, and weird thoughts during sleep deprivation.
This is how I feel when I've just come up with a story idea at four or five in the morning.