is a 3 week period normal ?!!

Steph
I'm 2 months pp...and formula feeding my son ..I've been on bc pills for 1 month now and my period has been goin on for 3 weeks now !...it seems like it's never gonna end ...mine never lasted more than two or three days before baby number 2 .Has this happened to any one else ? Is this Normal ?...just feel like it's never gonna end