help!!

sorry this got so long!!

so i have a smell down there, and it’s not fishy just really musty and gross. i know your vag is not going to smell like flowers, but it’s definitely not a smell i think is normal. i’ve gone to the doctors twice about it. once they gave me pills i couldn’t take, i then went back and got a gel. after doing the gel for 5 days, it sort of went away, but came back recently. i think both times it was some sort of bacterial infection, but i’m not 100% positive. my older sister(who’s basically my bestfriend) asked if it could possibly be an std. it got me thinking, but all of the stds i’ve learned about didn’t only have a smell, as i don’t have any other symptoms. any advice? i’m going back to the doctors within the next few days for another check up, and trying to get it figured out. just wanted to see if it could be an std, any ideas of what it could be? help a girl out!!