What can I do to feel better?

'm your classic teenager. I stay up late at night and sleep in during the summer. I've noticed something strange though. I'll stay up for sometimes over 35 hours at a time, and not be tired. I'll try to sleep, but I usually sit there for hours at a time, with no sleep. If I do sleep its for only a few hours at a time. Then I'll stay awake for another extremely extended amount of time. Its been about a week of this odd sleeping schedule and I've noticed other things as well. I've an immense decrease in appetite, and I feel sick if I eat to much. I force myself to drink enough water, even if it upsets my stomach.When I do eat I try to eat fruits and vegetables, things that are healthy, with things packed with fat and protein. Due to this I've lost a considerable amount of weight and it is begging to worry me. I have an odd little bruises on my leg. I also have extreme headaches that come on gradually. I'm paler than I usually am. I also have a unpleasant tugging sensation in my neck whenever I move it in one way or another. I'm not depressed, I'm actually really happy. My period was over two weeks ago, so I know it's not that. I'm not anorexic or bulimic, and I haven't had a history of it, nor have I ever had trouble sleeping. I want to know if there's anything I could do personally, before talking to my parents. Help Please?