Why am I still bleeding 3 weeks later.... (sorry for the long post)

Sarah

I was having the injection every 12 weeks for years since 18 but was bleeding for weeks on and off so I started having the injection every 10 weeks which helped and only bleed like once a year for a few days. (I went on contraception because I was really ill from my periods (being sick, the worst pain and cramps, could barely move due to back pain) I decided this year to change to the implant because the hormones are better apparently. I should probably say I am limited to what contraception I am allowed due to health conditions in the family. So 8 months of the implant I started my period and I'm about to going to go the 3rd week of bleeding, every day but nothing at night and no pain! I'm just wondering if anyone has experienced the same or has any advice... Before I speak to a doctor, which scares me.