Not sure what to do.

Okay I really need some advice! I work with older adults who are mentally disabled and we have this one client who is really aggressive. For awhile my boss was okay with me not working at this home with him but now she is scheduling me over with him again. I expressed my concerns with her and she doesn’t listen. The last time he attacked me he ripped my hair out and punched me. I’m afraid one day he will hit me in the stomach. If I wasn’t pregnant I really wouldn’t care if he hit me. Can she force me to work with him?