Difficulty in Defecating before Period

Hello everyone, why is it that for like two days before my period, I am not able to defecate and my stomach becomes big until the period starts?

And again, for like three months back now, I noticed that I purge for like two to three days, then no going to toilet again for like two days no matter what I take or eat, until the period starts? Please I need answers thank you.

I just want to suggest that it could be endometriosis. I normally have those symptoms prior to period. So you have pain during sex?

Thank you for your response. No I don’t experience pain during sex.