I Have a Wicked Stepmother

MY LIFE IS A LIVING HELL WHEN I GO TO MY DADS. SHE KEEPS ON FEEDING ME SHITTY (Just Peanut butter and that's all yuck!) SANDWICHES EVERYDAY FOR LUNCH AND LATER I START TO THROW UP. SHE ALSO BULLIED ME BY SAYING YOUR "LAZY" "RUDE" & "MEAN"
I don't know what to do now. I'm 18 and I don't talk to her because she DOSEN'T TRUST ME.