What are warning signs of depression?

Any of these symptoms during and after pregnancy that last longer than two weeks are signs of depression:

Feeling restless or irritable
Feeling sad, hopeless, and overwhelmed
Crying a lot
Having no energy or motivation
Eating too little or too much
Sleeping too little or too much
Trouble focusing, remembering, or making decisions
Feeling worthless and guilty
Loss of interest or pleasure in activities
Withdrawal from friends and family
Having headaches, chest pains, heart palpitations (the heart beating fast and feeling like it is skipping beats), or hyperventilation (fast and shallow breathing)