light pink discharge after protected sex

i’m on the depo shot and i’m about to take my next shot in the next week or so. had unprotected sex last week and had protected sex this week since I didn’t want to risk anything that involves pregnancy. today i’m getting a light pink discharge and my vagina still feels sore. i heard that pink discharge could be from rough sex or it’s implantation bleeding. any advice or suggestions?

i’ve been spotting these 3 months i’ve been on the shot. oddly enough, i wasnt spotting at all last week but i started spotting right after i had unprotected sex - it only lasted 3-4 days and i started to not spot anymore after that (but no pink discharge or anything abnormal).

tempted to buy a pregnancy test just to be sure i’m not pregnant but i feel like i’m overthinking it since i’m on birth control.