I get very angry sometimes. Should i do?

I'm surrounded by some persons who are very jealous of me and they are from my boyfriend's family. She is my boyfriend's own elder sister. She is married. She thinks that I'm snatching her parents from her even I'm trying to make my boyfriend apart from his family. But i never said such kind of things. She is very insecure about her family members. I used to go my boyfriend's house two to three times in a week and she never liked it. But my boyfriend's parents were so happy to spend time with me. She never liked it that's why she told them few bad things about me just to keep me away from them. Even once me,my boyfriend and her husband were talking about a topic and she was not there. My boyfriend just left the room for picking up a stuff from another room and she came just to check what was I doing and she kept the room's door wide open. I don't know what was her problem. Since then she is behaving very strangely. I feel very bad for her behaviour and words. What should i do?