just got bfp on rainbow baby but I'm spotting a day before af please help!

Hi guys! I'm wondering if I should be worried or not. Got my bfp 3 days ago and today I noticed when I wiped I had brown discharge. Not a lot. AF is due tomorrow so I'm wondering if it's a chemical or if it's just old implantation bleeding? I did notice an hour later i had a tiny but of red mixed but not a lot. What do you think? I'll be making an appointment Tuesday.