they are just jealous of you, don't stop being nice to people who hate you thats the only thing i do when someone hates me for no reason.
just ignore these kinds of people. just because you are nice doesn't mean others will be to you but that is their problem not yours. what ever you do to make yourself and others happy should not be dictated by how jealous they are of you. keep doing you and be more confident, takes a while but you'll see a change when you block out the negative people and do what you love. hugs