I am on the pill too, but I get monster cramps from time to time. It's because of the Tegretol I take for my seizures. It messes up my cycle and my periods don't always come on the "green" pills. Hence the monster cramps. I usually take Midol, or ibuprofen to get through them, and I eat lots of chocolate. I haven't tried those thermacare heating pads for periods though. I might have to try them.
I feel for you. I hate cramps, especially if I'm at work. I get moody and nasty to everyone. I'm glad it only happens once in awhile that I get them. I think I will never go off the pill just because of that fact.
Go home, rest and have someone bring you Midol, heating pads and chocolate!