They're petty retards and one of them was probably initially jealous of something about you.
There's nothing you can do. You did nothing but exist. Some people bring a highschool mentality with them into adulthood and you fell victim to someone's insecurities. They're vapid and get a high off of social drama.
As long as your breath and body don't smell bad, don't interrupt people, don't violate people's personal space or rights as a person, don't have a irritating volume, aren't publicly saying things that could offend someone, and basically just having all of your manners down, nobody has any valid reason to dislike you.
In short, you dindu nuffin' and need to not worry about people like that.
And if you're feeling extra put off by one of their face turns or dirty stares, one of these days you can ask either calmly "yeah what's your problem" or aggressively "what the fuck is your problem anyway?" and see if they could even respond.