Can someone tell me what bug or virus I might have?

So the last 3 days I've had a pounding headache. Whenever i've tried to get up or bend down and get up or move my head too fast my head starts to pound. When I sit still my head is pretty good except I can still feel it a little. I've had a concussion last year and It doesn't feel like that. Sometimes I'll feel sick to my stomach so I can't eat, but won't throw up. That and my back and neck are very stiff from time to time and will have to stretch it out and my legs will become wobbly when I get up. Can someone please tell me what I might have and maybe how to get rid of it? Please and thank you.