What Causes Diarrhea And Flatulence During Menstruation?

Last night I woke up around 0200 with watery stools and awful gas, which is very unusual for me. This morning when I woke up I noticed when I would fart I would produce blood tinged mucus. At first I had speculation that it came from my rectum as I am currently menstruating. BUT I m positive that it is not menstrual discharge.