mother in law more like monster in law

My fiancée and I are having a child. Due April 20th. We told my mother she was excited, he told his mother and she seemed ok at first until the next day then she started to freak out at both of us. Demanding I get an abortion (I don't agree with them for myself) we told her no and she begins to try and convince him I'm a whore and that it is not even his child. Although we both know it is his 100% she doesn't believe it. Now she is telling him to leave me and that it is all my fault and that I ruined his life. Then she brings up the fact that I had a miscarriage with an ex which is none of her business but she over heard me telling her son. This has gone on for two weeks now 🙄🙄 what do I do?!?