Can't take it

I'm 23 years old and due to financial hardship, me and my 2 year old had to temporarily move back home with my parents. I've only been home for a week and already and I'm extremely unhappy. My parents are very well off financially, so this is the most stable place for my son to be while I get back on my feet. Ever since I've been here, she's done nothing but criticize my parenting, undermine me when I try to discipline my son, and tell me that I don't make my son my first priority. My boyfriend and I have been working as hard as we can to support our children (he has one from a previous relationship). His daughter's mother refuses to keep a job, so he has to take full financial responsibility for that child as well as half of mine. In the one week that I've been home, I've had an interview for and gotten hired for a full time job. I'm determined to do what I need to do to get back on my feet but I don't know how long I can stay here with her and keep my sanity. Since I've been here I've been depressed, having chest pain, and having a short temper with my son. I don't have many other places to go. I don't know what to do.