What Causes Menstrual Cycle Inspite Of Having Ovaries Removed?

I recently received the cortisone injection to my lower back for the first time. The left side of my stomach was hurting terribly,and I had an extreme headache. Several days later my mentural cycle started and I had both of my ovaries tooken out about two years ago and I was told that I will no longer gave a period...please help me on what to do.