Depression will rob you of joy, erode your appetite for life, and leave you blaming yourself for any/everything.
In those circumstances where you cannot defeat it, you can still outlast it.
Do what you can for yourself. When you can do no more, do what you can for the person you will be later, and, when you can do no more: forgive yourself.
Depression is a parasite and it's been eating your strength far longer than you realize.