Decreased threshold for frustration post pregnancy is common especially due to the stress the body has been through and the added responsibilities. In such state important is to have a positive perspective and to be nurturing towards self and the child.
Such a things is hard to deal with and it would take persistent efforts from you and your husband. You have to tune up the understanding and division of responsibilities.
Next Steps
Consult Psychiatrist to start with appropriate antidepressant and counselling for the couples.
Health Tips
start with Counselling and ventilate your emotions. Meditation would help too.