Bleeding still 8 weeks postpartum

Bleeding did stop around 4 weeks postpartum but now I’m having this red coloured bleeding for the last 4-5 days, im breastfeeding and on the mini pill which I have never had a period on before, doctor said if I’m still bleeding in a few days I may need an ultrasound? On my maternity notes it said placenta intact so surely there can’t be any pregnancy tissue left inside at 8 weeks postpartum? This is what colour it is and it’s mainly on the tissue nothing really on the pad