What should i do about my boss, dr jeckyl and ms hyde?

she can be really nice cometimes, and really horrible others!! a few days ago, she called my dr's office with the intention of getting me to change my appoinment! THEN, her son in law works next door and she goes off to him about my maternity leave and if im coming back or whatever IN FRONT OF ME!! i havent decided what im doing yet, but im only 11 weeks!! i dont know if i should look for another job or what....i need some kind of benefits....should i change jobs?? help!