Under the right conditions it can be very helpful to work on bad things that happened in the past, but I wonder if you are in a fit state. See the FAQ on childhood trauma on the Psychotherapy page of my website. You might want to get a second opinion from a psychotherapist with a lot of experience with childhood trauma and depression. Try to find a kind of exercise that feels good, or at least does not feel like a drag. Exercise is very important for depression and insomnia.
Nutritional deficiencies can adversely affect the brain and the emotions.
When you have a setback, don't give up. That will give you a further boost towards recovery, because not working usually tends to perpetuate depression.