Fast heartbeat, bloods rushed to my head,jumpy, somewhat dizzy, hot&cold flashes?

[AshleyW]

I am only 18 but right now I am feeling so strange and weird. Like I never have before. It feels like all the blood has rushed to me head. My heart is pounding so fast and I am so jumpy i can barely type what I am wanting to say. I feel somewhat dizzy.I am freezing and then in a little bit be burning up. I don't feel right and I don't know what's wrong with me. And there's no possible way I can be pregnant(just so you know)