implantation or start to my period??

so im on the mirena IUD (comes out today) i havent had a period since 6 months of insertion (5 years ago) not even spotting. this morning when i wiped i noticed what looked like old blood (brown) but only on my tp and not my panties. second time i went to the bathroom this happened (same SAAthing as before. only shows up on tp and not my panties). is this implantation spotting or the start to my period. im so worried. please ladies, HELP!! thanks (: