What Are The Side Effects Of Mirena IUD?

i have been having a menstrual like bleeding for about 2 months now....about a month ago my doc sent me to the er and they said everything was fine i could be caused from having my mirena removed in october...they prescribed me some progesterione for 10 days well it stopped while i was taking it but now it is back and hass been for like 2 weeks...the bleeding is heavier and the cramping iks seriously painful i called my doctor to get a referral to go see a gyno but they haven't called me back with an appointment yet..i don't know what i should do should i go back to the e.r. or should i wait and i forgot to add that i have been passing heavy clots and been lightheaded with this