Talk to Gynecologist on Abnormal Uterine Lining Shedding

Assalam-o-Alaikum doctor. My normal cycle is 26 days. Last month, it stretched to 36 days. I had brown spotting for a whole week mid-cycle (13 days after my period). This month, my period came, but now exactly 14 days later, the brown spotting has started again. I also noticed that right after my period, eating dairy or spicy food causes sharp stomach pain that goes away after using the washroom. I am not taking any birth control or emergency pills. Please advise.