What Causes Womb Aches With Irregular Periods And Discharges?

8 months ago I gave birth and in November last year had a non hormone coil fitted. My periods are still not regular and recently I have been having dull aches in my womb and down one side of my leg together with a brown discharge. Should I see my GP? I am 23 years old, 9st olbs and 5ft 5ins. I have had anemia since my baby was born for which I took iron and during the pregnancy I suffered with hyperemesis. Otherwise I am in good health.