MIL. How to stoo being angry at her? I dont want to hurt my husband

Help needed! yesterday my mil sent me one cold nasty email. She stated that basically i am an awful human being and they both with her husband cry about her only child(my husband) ,because he is so unhappy. that nobody likes me from his family. and "if men does everything,why does he need a female?".

i cant deal with this. I am in lots of physical pain since last July. I was pregnant at that time as well -25 weeks. and we went to see my husband parents who live 2000 km from us. We drove with our car. and in three days we were there. i was swollen af and in deep pain from my last epidural and new baby was laying on my spine. it was awful. anywaysn i was nice to everybody. i asked for help to my husband with kids and said that he cant swim when drunk-because when we were at his family house everybody were drinking,couldnt walked straight and went to the lake. I had a few accidents in my family when they stupidly drunk their asses of and went for swiming. anyways. now she says that in controlling(im not i swear,he can do whatever he wants,when he wants,i will always be behind his every choice,the samw with him. i love our relationships. and now she is basicaly saying im a shitty wife,mother and a human being fir asking help from my husband when i couldnt do things because of my pain. like literary my third pregnancy was awful. with my first i was running things till the end ,but with this i was half dead,since 15 weeks. my husband is pissed of because of her email. she said that she knows we will split up and our relationship isnt normal. am i overreacting? i did then and do now as much as i can. do i have to prove myself to her or just ignore her? my husband will talk to her next time when we will meet. there a much more things she has done,but this post is already too long. any advice would be nice! Thank you for your time!