2 periods in one month

i have recently got back on birth control in September to regulate my cycle so i can have a baby. My cycle came on October 3-7 when i found out that i would be ovulating the weekend i stopped taking birth control. I went to the bathroom and there was this brownish bloody discharge so i wipe and it was still the same. later on that night i got the worst cramps ever i couldn't even sleep so i went to the bathroom and there was no blood on my pad but a little gush of blood came out but when i wipeit was light pinkish blood. I'm having lower back pain and cramps only on my left side.. Help!!!