family calling me a SLUT!?!?

A year ago I moved in with my uncle. So I wasn't by my judgmental family members. Well a month ago my boyfriend came over to my house to surprise me for my birthday and he came to my room and we started to have sex well no one was at home at the time. Well I never got the message that my sister was going to come over and she's 16 and she has a key well she came in while we were doing it and I was so embarrassed at the time. She left after awhile and him and I left. She told my entire family. Now everytime I'm with them or anything that's what they call me. My mother today called me a whore and a shut for just wearing shorts. I'm getting to the point I don't even want to be around them and I'm 19 years old I think I have the right to make my own decisions