Does anyone know why I'm getting muscle spasms in my uterus?

I'm a 20 year old college student and I've been having uterine muscle spasms for like the past 2 days - constantly, ever minute or so. I am NOT pregnant nor am I on my period. This seems to occur every once and a while and last for a few days. I am not a vegetarian though I haven't been eating red meat for a while (our college doesn't serve red meat because it's too costly for so many students). Could this be dietary? Why is this happening?