Regulating cycle?

I had my daughter September 2015. Got on Mirena from November to May and decided it wasn't right for me and switched to the pills up until August 19th (my husband decided we were ttc #2). AF decided to come the 24th, returned on the 16th of September and was everything but a normal period (huge clots with turning over pain that I chalked up to be my body's way of trying to regulate). Now obviously I'm confused when to expect AF. On here it says the 9th, my last AF was the 16th. On Mirena I spotted all of the time and nothing was AF like, and when I switched to the pills AF was light and barely existent. Help?!