Implantation Bleeding or something else?

Saturday, I felt a gush and thought I started my period, and I’ve have pink and brown mucusy discharge everytime I wipe, and it’s going on almost five days of this now. I went to the ER because I had a miscarriage six months ago, and was nervous, and the blood work said my HCG was 8,918, I was five weeks two days at that point and they couldn’t see anything on both ultrasounds they did. I have blood work again tomorrow and Monday, but has anyone went through something similar?

Also, I understand it might be implantation bleeding/spotting, but would it last that long? I’ve read everywhere that it’s only supposed to be 1-2 days.