Is it normal to feel sick 10 hours after fining blood?

I'm 17, and today was my fifth time giving blood. I have not had any problems with it until today. When I got the needle in it hurt a lot more than usual. The nurse wasn't paying attention and my blood bag filled up so much that it fell off the hook. She was able to take it out okay, and she acted like it was fine. Immediatly after giving blood I felt like I was going to throw up and was seeing spots. I ended up staying in the office for over an hour because I went completely white/pale and just about fainted twice. Its been 10 hours now and I feel like I'm sea sick, and keep gagging and seeing spots. I also feel completely physically drained. Should I be worried or am I just overreacting? Please let me know.