I need help. :(

So I had sex w two guys the past month, ny vagina is like foul smelling now. It could be a std but idk, I’ve been bleeding for almost 3 weeks and its just spotting but today and yesterday it got a tad heavier and it’s like almost a black color. I’m worried and I made an app to get tested for a STD and STI .. but I’ve been having cramping and shit which I think has to do with my period but if I wear a tampon it literally smells like shit. I feel so self conscious about it and I don’t know what to do because I’m usually super clean and smart about this. If you have any at home remedies please recommend, I’m only 18 and I really don’t want my parents to find out anything:( I should mention I’m on the implant so that could be why I’ve been bleeding but idk🤦🏽‍♀️