Are you in touch with your local ABA group? If you can, screaming baby or no, get along. you'll find some understanding mums willing to bring you a cuppa and cake.

Day to day, how much help do you have? You sound pretty isolated, which only makes it all worse. We're not really designed to do this alone.
Do you think you could have a chat about how you're feeling with your nurse or doctor, or a family member or friend? The adjustment period is normal, and in our modern world trying to do it all it's (unfortunately) quite normal to struggle, but there's definitely a point beyond which you really need help.