WTF period..

This time last year I fell pregnant at 16 and ended up having an abortion on the 1st of February, as my boyfriend at the time didn't want to keep the baby. In the UK (where I live) its procedure to be place on some form of long term birth control the day of the abortion, I chose the injection and had my first that day. Everything was fine while on the injection, I had little to no periods however I gained about 3 stone while on it due to increased cravings and hormonal imbalances.  After the first three months I was due another injection , this was around may, which I received. This turned out the be the last injection I had as I broke up with my shit bag boyfriend and didn't see the need anymore and wanted to get my body back on its natural cycle and see if I could shift the weight I'd put on whilst on the injection. This was around July time I made this decision meaning my injection would not run out till August. I had no periods from this time till around November which I expected whilst my body returned to normality, I got my period this month on the 10th and expected it to last 7 days as normal but wouldn't have been surprised if it was shorter/ longer. The first 7 days went as the normally would, my flow decreased to almost nothing on the 7th day but the next day it was very heavy. Now it was been 22 days and I am still on a very heavy period and it's becoming a concern of both mine and my current partners. Any sort of advice or reassurance would be greatly appreciated. Thanks x