2 and a half weeks ago I got my first period in 2.5 years (due to Implant insertion). It originally started off as red blood for the first few days and gradually changed to brown and dark brown and has been bleeding lightly for the last 2 weeks. Usually my periods only last 4-5 days but this one has persisted. In the past few days though I've noticed a rotten smell coming from my tampon on removal after 7-8 hours. I've tried searching my vagina for a forgotten tampon but cannot really feel anything up there, and the smell of the blood when removing my fingers smells like rotten meat.
Since I haven't gotten my period for such a long time due to the implant and I'm still bleeding despite it being abnormal for me, I'm not sure is this is a random unfortunate implant side effect and I just need to get my implant replaced or whether this is something completely separate. I currently can't really take time off work for the next 3 weeks as we are very busy. I don't really have any other symptoms but this (I have a small stomach ache at the moment but this has just started).