menstrual-like cramps FROM running

So this is going to sound weird, but ever since I hit puberty I have gotten menstrual-like cramps from running. I remember every time I had to the do (not-so)"fun run" in high school, I'd be curled over in a ball with horrific menstrual-like cramps afterwards, even though my period was nowhere near. For that reason, I haven't done any running since I finished P.E. Recently, I decided to try jogging on the treadmill. Big mistake! Just from 2 minutes of trying to JOG, I spent the rest of the night in pain. Anyone else get this? I feel like a freak of nature here. And, no, this isn't a regular abdominal cramp. This feels just like starting my period, even though it's not starting.