Contractions, NOT pregnant

This morning I woke up with pain in my stomach that felt just like labor contractions. It was wave like pain lasting about a minute, coming and going. It hurt bad. I thought I either had to poop or maybe I am gonna start my period soon but I still have 6 days until my period is due and I did go poop but it didn't help at all. Some of them are extremely painful, almost making me double over in pain. I didn't get contractions like this with my son until I was well into labor and about to delivery. What could this be?? I'm NOT pregnant or if I am I'm really early (10 dpo). I don't know any other way to describe them other than saying they are like contractions.

Kidney stones?

I have the same issue and my dr told me its from ovarian cysts

maybe you are starting your period soon.
this what my "cramps" feel like 

Your uterus contracts before and during your period.