Living with my inlaws

So basically, I've been married for almost 5 years now. I am pregnant with my 2nd child, my first is 2,5 years old.
I live with my inlaws and have done ever since I got married.
The thing is, I don't dislike them and we do usually get on, I just want my own space and my own house.
My husband doesn't want to leave his parents as he is the only son and I'm fine with living with his parents but I don't want to live with his sister. He has two sisters, one of them is absolutely lovely, the other one is horrible.
I don't like her at all. She makes life difficult for me purposely, she steals my stuff and if I look my room door she breaks into it.
We have many times tried to confront her about this but she just denies it. My MIL gets angry at me as if its my fault and claims that my sisterinlaw has said that I am stealing from her and not the other way around.
I had a huge argument with my MIL the other day because she was getting angry at me for telling my husband about his sister and her wrongdoings.
I know myself that I havent touched any of her things or ever stolen from her but now my MIL is telling my husband that I'm a sly, thieving, deceitful person and I can't be trusted?!?!?!!! My MIL has always taken her daughters side and never really handled the situation properly, which is why almost 5 years later it is still happening.
I just dont know what to do anymore, I've tried being nice to her, I've tried being her friend, I make so much effort with her and things still hasn't changed. Now she has decided that she doesn't want a relationship with me and its just really awkward and weird living in the same house as her.
My MIL isn't talking to me either because of this issue and also because she got angry at me for not making her husbands dinner and her dinner when I was putting my son to sleep, which I explained to her that isn't fair because either way I am going to put my children before anyone else. My child and my husband are my first responsibility, I didn't marry my MIL or FIL and I have never had an issue with cleaning and cooking for them but if my child needs attention and care then that comes first in my head, am I wrong?
My MIL got so angry that she said some pretty horrible things, calling me a bad wife, a horrible mother and that her house has turned to *****after I've moved in and I should just take my son and husband and get out.
I didn't respond to this, I simply just got up and walked out of the room as she was fuming. I honestly don't really want to stay in this house atm, especially with being pregnant and just trying to be happy.
advice?

Edited by Sophia123 - 18 May 2016 at 1:00am

And housework is like office work you have to sweat or someone will have to sweat but work has to be completed.it does require commitment,effort,and some daily lack of sleep also

Assalamalikum how are you.as you are pregnant you should take good care of yourself and don't take unnecessary stress as pregnancy is always very delicate.leave all your problems to Allah.you are lucky that your mil is saying all this if you were at war with sil it would be very very horrible .I feel straight path is always the easiest hence forgive people in your heart .if you wish something bad should happen to them also still the will get the good fortune Allah has decreed for them as for there punishment for anything bad they do to you or anyone that's none of our business Allah will take care of that .

Sultana99 wrote: And housework is like office work you have to sweat or someone will have to sweat but work has to be completed.it does require commitment,effort,and some daily lack of sleep also

yes exactly