My family is driving me crazy.?

ok so i am blessed with a six month old baby girl. Me and my husband had to move in with my parents because i had to quit work after gwen was born and we just couldnt live on his income. my mother was fine with it. she sold her place and we all went in together and rented a huge house. Well since we moved in here and even at her old house she doesnt want me to leave the house. I understand my mother is under a ton of stress and i dont know how to help her more than i do. but i need to get out of the house. See i had gestational diabetes and gained 100lbs with my pregnancy and have had health problems every since and have been diagnosed with post partum depression. i literally feel like im going nuts sitting in the house day in and out. Its winter here and im not ALLOWED to take my daughter out because my mother says she will catch something because its cold. I have tried telling her that i will cover her up, dress her warm and the vehical would be warm. But she just makes me feel selfish and tells me to think about the baby not myself. Has anyone else been in this situation? What can i do?