Anyone else this

Last month on the 27th i had really bad belly cramps 10 after my period i couldn't shift it all
So yesterday was the 26th and all day i had the same pain. Feel like cramps in middle of my belly and back. 9 days after my period lol
What u think it is ? Think I should go doctors about it Monday. Or wait an other month and see if next month does the same?
I have had unprotected sex on the 28th july had my period 11th had sex on the 5th day i was on ( only there when wipe ) and the 24 th this month.
Done test all neg x