help!

i got an implant a month ago. i had sex three weeks ago (8 or 10 days after getting the implant), on the first day of my period (a saturday). i bled quite a bit but figured it was just menstrual blood and let it go. the next thursday, when i did it again, the blood flow was significantly less but i got blood on his sheets as i started heavy bleeding again. its been 3 weeks and i’m still bleeding. is this something i should see a doctor about or is my body just adjusting to the implant?