Implantation bleeding

Is implantation bleeding always light pink? I’m 12dpo and I’ve had 2 faint line positive (11dpo &12dpo) with all of the same pregnancy symptoms as my previous pregnancies (extremely sore boobs, itchy nipples, extreme fatigue, nausea) I’m supposed to start my period Saturday but last night and a little this morning I’ve had some brown spotting. Not a lot, just a tiny bit when I wipe. I’m worried this could be a chemical and just looking for any stories of implantation bleeding being light/medium brown or if anyone spotted brown and they were fine!

Thanks in advanced :)