HELP, freaking out thinking this may be implantation bleeding need advice please 🩵

Anika

I had sex this last weekend at my peak ovulation time. I used protection every time, however this weekend am experiencing very light cramping and a little very dark brown discharge. It looks like old blood mixed with discharge. Could this be anything other than implantation bleeding? I also want to mention I just upped my dose of spironalactone and am on antibiotics this week idk if that makes any difference. Thank you!!