My mother in law is killing me!

I'm so moody and hormonal and my mother in law is driving me crazy! This woman is up my rear! Also she's a step mother in law and her son's daughter is pregnant too, she doesn't know about me but suspects and it feels like she's trying to sabatoge me! She's trying to stress me out by arguing with me and she came in while I was doing yoga and stomped on my stomach!

What do ya'll think? I really need advice how to handle this one cause I'm out of patience!!! Being 39, only 6 weeks and 5 days, I'm fragile still!! This woman is insane!!!