Weird symptoms

so this is weird. Basically on June 5th I had unprotected sex like several times. This was a few days after my period ended. Ever since then, I haven't had a period. A couple months later I felt weird and thought I could be pregnant but I might've just been psyching myself out. I took a test and it was negative. So I let go of that idea. Fast forward to now, 108 days since my last period, and I still sometimes feel weird. I've gotten pretty drunk probably 2-3 times since and the day after my uterus hurt like I was gonna start my period. But never did. Everytime I sneeze My uterus hurts really bad for like 1 second. I'm starting to think somethings wrong. I'm sure I'm not pregnant cause I took that test that was negative but i don't know. I know I need to go to the doctor and I will. Has anybody else had a similar experience?