Anyone help? Don't know what's going on

I had my gorgeous baby boy in March 2015, had a normal period like a month or so later, went on the injection birth control but it made me bleed for 2/3 months straight and made my hair fall out and since I stopped it my period hasn't been normal since.
I didn't have a period at all in November but I wasn't pregnant (i did like two tests every week :p) and now I've got my period (got it before Christmas) and still have it but I've had it for over two weeks now! What is this? Has anyone had this?