Pull out method fail? & Really bad cramps?

I’ve had really bad period-like cramps for the past few days in my lower back and in the front and I’m not due for my period for another week or so and I’m kinda worried. My boyfriend and i have been using the pull out method and I don’t think I’m pregnant because it would be too early to tell I think. But I can’t think of any other reason why I would be getting cramps in what feels like my uterus (because they are in the same place as my period cramps exactly).

Let me know if any of you have experienced anything similar in any regard :) anything helps

To clarify: I’m not constipated even tho that’s what google seems to think 😂 & i have had my period for 5 years and have never had bad PMS before so I don’t think it’s pms & I’m a few days past ovulation