Making parenthood easier in the first few months baby #2

So with my first child 4 years ago I had extreme postpartum depression that turned into long lasting depression, I then became a less than adequate mother, I was a single mother, and now my child is with my parents more than she is with me (though I do have full custody), i already am feeling pretty terrible that I am pregnant with another child but I can't just not have a baby because my circumstances are less than ideal.