I went through a very difficult time when I moved from one city to another and took a new job at a different school. I was hired in a supervisory position, and when I arrived, the other teachers in the school were upset because none of them were promoted to the position for which I was hired. As a result, a rumor started that I was a "spy" for management, and I was not trusted.
I learned early in life that we cannot change how people perceive us simply by going up to them and explaining that they do not perceive us correctly. Just talking will not change anyone's mind. We cannot try to change people's opinions unless they are willing to change those opinions. The best way to change their opinions is to simply continue to be yourself, and allow your own actions to be your words.
If you are a friend to others and ignore what they say about you, then you will show them that you are a good person, and they will start to question themselves. They will ask themselves, "Why do I think poorly of him/her, when what I see is not what I thought I would see?"
For me, it was the same. I had to continue to be "me." I was friendly to all, even to those who treated me badly and spread the rumors. It took a long time, but eventually my coworkers realized that I was not the person they were told that I was. We became friends.
I found this to be true with some of my students as well. In particular, I remember one girl who seemed to hate me from the very first day of class. When I would say something that made the other students smile or laugh, she would just roll her eyes and look disgusted. It was as if she were saying, "THEY might think you're OK, but *I* know better." I had no idea why she felt this way, but it did not change the way I treated her. I was friendly to her just as I was to all of my students. I asked her the same kinds of questions I asked the other students. I encouraged her to elaborate on her opinions in class, just as I did for all of my students. After several months of the school year had passed, I saw a change in her. Her attitude towards me softened, and she actually seemed to enjoy the class. Eventually, she was happy in my class and shared her opinions without my having to coax her to speak. She had changed dramatically. I had short conferences with my students from time to time in order to help them do better in class, to encourage them, to evaluate their work, and to ask if there were anything I could do to help them to do better. When I spoke with her, I asked her what had happened for her to have changed her actions so dramatically. She said, "Before I came to your class, I was told by ______ that you were a phony. He said you would be all smiles and would talk about encouraging everyone, but he said you were actually a very mean person who never meant what you said." I asked her, "What happened? What changed?" She said, "Well, after a while, I realized that what I saw from you is really who you are, not what _____ had said about you that I believed back then. So I decided to give you a chance, and now I think you are a good teacher."
That conversation is one I will treasure all my life. It is also one that I remember every time I find myself in a situation where someone does not like me, for some reason. So here is my advice to you: be yourself. Don't allow other people to shape who you are by their negative words or actions to you. Continue to be a positive person, have faith that eventually, they will understand that the person who said these bad things about you was wrong. There is nothing YOU can do to change THEM. They must change themselves.
Best wishes to you.