WOMEN! what are your experiances with Mirena?

okay soo i had the mirena inserted about 2 weeks ago and pretty much ever since ive been having quite a lot of cramping mainly on the left side. Well about three days ago i started to spot nothing serious well then yesterday my period got REALLY HEAVY kinda scary to be honest. so i made sure i bought a lot of maxi pads and super tampons. (since im leaking right through the tampons) so when i woke up this morning i changed my pad and tampon and about 2 hours later i feel my pants are wet ! im thinking this cant be right! wtf! sure enough bled right through both! and when i went to the bathroom i noticed HUGE blood clots in the toiletm i even felt them come out. i have NEVER im my whole life bled like this im starting to get a little worried, i dont want to lose too much blood. I knew that for the firt few months your supposed to have heavier periods but this heavy? im not liking this one bit! also i used to NEVER get cramps with my period and now there soo bad! what the heck! cont..