I am no expert here, I am a man and I have no kids.
But I have the feeling, this is due to low energies in the mother, as possibly the mother sends a lot of spiritual energies to the kid, to sustain his early weeks.
Normally depression is caused by low general energies in own soul.
Hope this helps.
After giving birth, a woman becomes more sensitive and receptive, and her feelings become more acute.
It is quite possible that after giving birth, your existing depression worsened, which you did not notice earlier, or continued to ignore.
The best way to deal with depression is to raise your own vibrations.
I recommend that you thoroughly cleanse your aura and chakras, as well as engage in programming your aura, which you can program so that you do not have depression.
Not sure, but fire pertains to optimism and health and the moon pertains to motherhood and emotions. Therefore, both Sowilo and Berkano could help in their own ways.