Maybe you're not overly sensitive, but highly sensitive. The book The Highly Sensitive Person by Elaine Aron really validated my gift.

http://www.amazon.com/Highly-Sensiti...162&sr=8-2

I agree that teasing is counterproductive. It's also passive agressive.

p.s. As an adult, I finally stood up to my mother and told her that telling stories on me really hurt my feelings. She got angry and told me that things happened to her too. But she stopped teasing me. This was after years of therapy. I hope it doesn't take as long for you.

When you see your sensitivity as the gift it is, then you will never be shamed for it by another. Oh, and also, a good comeback is, "It is not possible to be too sensitive." or "well, you are insensitive."