Being tired... but not

I felt tired, despite the amount of coffee that I drank, which is enough to cause a heart attack. So tired that I was falling asleep at my desk. I was tired when I crawled into my bed. I was tired all the way until I tried to finally close my eyes. It's only 18:00 (5 p.m), I have no reason to want a nap, but I do Why does this happen? Like when you're staring at something to get sleepy, and then you feel sleepy, but when you actually try to sleep, you can't. 

That sucks when you're studying... I never study so if I am then it is very important, and just that feeling of being tired. You push through it, but the words in front of you blur together and the feeling of closing your eyes and disappearing from this world seems so appealing. Then to have that great feeling of release to be taken from you and thrown into next week. It's awful.

I've also had the opposite happen. I've felt super energetic and happy to be alive, only to have that feeling ripped away. Now, granted, it was only taken away because I saw a certain "friend", but that's besides the point. My mind can be so active, yet I feel like dying. Almost all my moods when my friends ask how I am... is tired... I'm tired, always tired.