Try Nioxin. They give that to cancer patients to prevent balding during kemo and I can attest that it works VERY well for nearly ANYONE who is balding. It's not very expensive either and you can find it in salons.
It feels good too. Very tingly and minty :)
ALSO - have you talked to your doctor? It could be something very simple like a vitamin deficiency. I'd suggest seeing your doctor as well.