Please help

I got the nexplanon on December 21st. 2 weeks after postpartum Vist.

1 week after I got the nexplanon I started bleeding.

I haven't stopped bleeding. Some days are really heavy and others are light. No blood cloths. It's been 17 days. On the 11th day I called my doctor and the office lady told me it was just my body getting use to the birth control but my doctor never called me back.

Is this normal?

Also this is my 4th one and it's never done this before.