Mental stress because of my in-laws

I'm a working women. I got married 2 years ago. Its a love cum arranged marriage. My in-laws are blessed with a younger daughter aged 21 and a son i.e my husband. My mother-in-law has ill-health but can do her own things. She can go for shopping , she can wash her bathroom, she can do poojas but she cant do cooking. As my best I cook for them and then leave to office. But sometimes I may not cook for which she humiliates a lot. She tells that cooking is my responsibility. My concern is that I have 24 hours of which I will travel 4-5 hours per day, stay at office for 9.5 hours and sleep for 6 hours. I will be left with 3 hours in which i need 1 hour for my personal things. in the remaining 2 hours i'll do all the household works till the time knocks. They never cared about my travelling and work stress. Despite my stress , i have to cook, give money and not to answer her when she scolds. She scolds me and my parents a lot. I used to cry a lot and sometimes i feel like killing myself. My husband says as he is the only son, he cant leave parents and as his mother is ill i should not tell her anything and should shut my mouth if she barks. My parents are blessed with me and my sister. we sisters are married and stay away from parents. my parents stay alone. then why cant my husband's parents live like my parents? why cant they leave us free from stress?