I had my third child in June. Had my first period in July and went back on birth control. In August I had 3 cycles, Sept. and Oct. only had 1 each month but was a 22 day cycle, then in Nov. I had 2 full cycles with spotting in between. All of this while taking birth control. My doctor gave me a prescription for a different BC to try for the next few months. I have always been very regular until now. Has anyone else had this problem or know what could be going on?