Ok so I was due to get another dosage of depo going on a month now but I decided I don’t want birth control anymore and I got off of it

Ever since me and my boyfriend have been having sex really frequent after that, now today I seen this. Normally when I start my period it’s a bright red or even when I’m about to start, but this is brownish pink, so i don’t know if this is implantation bleeding and I could possibly be pregnant?

My nipples have also been hurting and sensitive

Edit: I should have mentioned but I got pregnant with my 2nd baby right after getting off of birth control but I had the implant at that time