I am fortunate in that I have never suffered from any kind of motion sickness. My instructor tried to demonstrate spatial disorientation to me during my IR training, and ended up feeling a bit queasy himself, even though I was the one under the hood!

I have a good friend who started lessons but got sick on every flight and in the give up with the training. Sometimes you have to accept it is not going to work. Most OTC medications for motion sickness are not approved for airmen. If you belong to AOPA they have a good resource for determining if a medication is approved or not. This is also a good resource:-
http://www.leftseat.com/medcat1.htm

Good luck, I hope you can find a solution, personal flying is truly great fun. If I could go back to when I was 18, I would have chosen a different career.