this is just normal high school mob mentality. one "cool" person (the ghetto guy) makes a remark trying to impress his friends. in turn, they feel that they have to not only agree with what he says but act upon it, or else theyre worried they might get shunned from the popular group that they want to stay in. girls will then take this on, to try and get in with the boys. there really is nothing in it, you're not ugly its just the way that kids act. dont worry about it, you seem to get on well with people outside of your school so try and meet more people like that so you dont start to think the people at school are right. as for when theyll stop - well it could literally be a few days if some weirdo transfers to the school and is an obvious target for these kinda verbal games, or it might be a few years when the people have actually grown up and realised that actually that ghetto boy is an idiot. you never know, its perfectly possibly that in a few years you could be friends with some of these people, when they realise that they should make their own judgements of people and not just follow the crowd to fit in.