As a 18 Yr old non sexually active female im not understanding why my menstrual cycle is gapping every 4 or 5 months I dont get it. Then I get it normally for 2 months and then it gaps again. This started about 2 years ago I had surgery done on my arm and they gave me a new medicine with an extremely long name. It hurted my stomach really bad so I stopped taking it . Can u help me understand why this is happening?