I remember that she was convinced somone wanted to kill her baby. It turned out she had a split personality, i think, and that was her all along. She was running around her own house with a knife.
Also she had a husband that was never home due to work. One time they were organising a party at their house, she wanted to dye her hair but she forgot to wash it off and burnt her hair.
I think it's a 90's-00's movie. I'm not sure if it's all correct, but that's all I can remember.