What Causes Severe Pain In Abdomen While On Implant?

hi, im severteen, i have had the contraceptive implant for a year and half now, i had a 1st period within 2 weeks of having it and it was fine its been great for a year and half, now iv been on for 2 months, i stopped for a week in the middle and just re-started again but dark brown blood. not red at all. im in quite abit of pain too, worse than before. iv been or a full screening and they'v come back all clear. Im sure its my inplant, its aches sometimes and its woke me up aching before. do you think it is the implant, im sure?