I got my mirena (levonorgestrel) in a month ago and i'm still bleeding with super bad cramps today. is this normal?

Yes, unfortunately: The Mirena (levonorgestrel) has to counteract hormones that your ovaries make during each cycle and this may take 3-6 mos. So be patient for now, however, call your gyn to discuss possible removal if bleeding lasts more than 6 mos.

Yes: Bleeding can persist for several weeks. As to cramping, any foreign body can cause it, and it is not unusual with iuds. See your physician for an exam.