Still on my period?

Okay so November 30th I got the birth control implant in my arm. I left for boot camp the 8th of December and I had just started my period. Well it hasn't stopped. I keep bleeding some days more than others like some days it like a normal period and others it seems like just spotting. It's kinda back to just spotting but I'm concerned. I've been getting really bad cramps as well. Is this normal and should I go see someone?