Stabbing rectal pain during heavy period!

Hi ladies, for the last few years I’ve been experiencing the worst pain when I get my period. It is this stabbing pain in my rectum (anus) that literally stops me dead in my tracks! I can’t move and the pain comes in spurts of 5-10seconds at a time. The pain especially comes when I’m trying to have a bowel movement during my period and it is mainly present during my heaviest day. I’ve looked up this symptom and Endometriosis always comes up but the more I read about the other endometriosis symptoms, the more I think this is incorrect because I don’t have any other symptoms but this pain. I know I should see a doctor, and I have been putting it off for years because some in periods I can manage the pain and like I said it’s only present on my heaviest day. Once I get past that, everything is back to normal. Just wondering if I’m crazy or there’s anyone else out there that experiences this exact pain. :(