weird vaginal symptoms

hi everyone, i’m currently recovering from the flu, and the day before yesterday i started burning really bad (cloudy and smelly urine, typical uti symptoms) so now im on the antibiotics. for what it’s worth, my period ended on the 6th, with a little leftover brown blood on the 7th. but today i noticed really fishy smelling brown discharge (and a lot of it) it kind of resembles the brown discharge you get when your period is staring. i last had sex on the 4th (protected with condom and pullout combined) also kind of paranoid this could be implantation bleeding?

i never have vaginal problems like this, and im still confused as to how i got a UTI or what this brown smelly discharge is.