Mirena and sporadic cramping

I've had the mirena for 3 months (10-20-17), insertion was a breeze, however 6 days in I and my doctors thought it was expelling l because the strings suddenly kind of fell out. I got home from work and started having vaginal pains only to realize the strings were jabbing into my vaginal opening. They rushed me in the next day and the answer was "we guess the strings got caught around your cervix before being cut and finally relaxed and fell"..... ok... So I haven't had a period in 2 months BUT almost every day I sporadic terrible cramps, equal to the cramps I had on the pill. I got the mirena because of SEVERE periods, super plus tampons every 30 minutes while wearing a pad and, cramps that made me black out, etc. So my question is, is this normal? Has anyone else experienced random sporadic bad cramps?