The brain fog you are currently experiencing could be down to two things...
Either your hormones are still trying to rebalance or your new contraceptive is causing it.
Since the mirena I can barely tolerate any drug it has affected me so badly. My brain for is still with me (I am around the 6 month post removal mark)and I only had the mirena for 10 months. This is frustrating as I'm a teacher and it seems I stand for ever at the front of the class, waiting for the word in my head to reach my mouth!On the bright side, my memory is slowly improving and that was really bad too at one point.