Cramps while on BC!?

Tried looking up some info on it, but all I got was "birth control treating cramps" and that's not my case- at all. So what's happening to me is this: I'm getting cramps. Weird, "I'm getting my period" type of cramps. Or my ovaries hurt on and off. Been on BC for 5 months and it's happened so far every month to me. I'm not due with AF until the next 3-4 days. IS ANYONE GOING THROUGH THIS? Or  experienced this at some point!?