Could Chronic Constipation Be The Cause For Early Menstruation?

i am 19 years old female and have been having troubles having BM s i went to my gastro dr and they are doing a coloscopy as well as an endoscopy next week. today i m having some concerns with abnormal vagina bleeding. i have been getting my period regular for over 2 years now. i am on birth control as well and not supposed to start my period till the 13th. i have had to do many enemas and suppositories to try moving my stool, but little results with these. could having chronic constipation be causing this? please help