What Causes Brown Vaginal Discharge And Stomach Cramps?

I m just going to start from the beginning. Over two years ago I was at a healthy weight of 145 lbs for my 5 9 female frame. I decided to get on to birth control at the age of 18 and I chose the shot. It worked well for the first month, then I started gaining weight rapidly and bleeding non stop, an extremely heavy flow. Being embarrassed, I told myself I would wait to see if it would go away, maybe my body just needed to get used to the hormones. After a year I decided to stop with the shot and I moved on to mirena. Since I made the switch I have had cramps, bloating, and dark yellow/orange urine constantly and had an occasional dark brown discharge. What s wrong with me?