Ovulating on the pill?

I have been on the pill for over 3 years now. I took yasmin for 2 years, yaz for one, and recently 2 months ago switched to generic yasmin. I have been having a cramping in the right side of my abdomen a few inches from my belly on for the past two days. At first, I thought it was my appendix, but I don't have that awful striking pain everyone talks about. The girls at work told me I'm probably ovulating. But I know the pill is supposed to stop ovulation, and I take it PERFECTLY, so why is this happening? Has anyone else ever had symptoms of ovulation while on the pill?