Covert Narcissist loves a Person with Depression

May 2021
South africa
I (Male 21) have been diagnosed with Covert Narcissistic personality disorder. My partner (Female 26) has crippling depression.

The problem is, when she gets depressed my logic tells me that she's being childish or irrational in situations, and I try to change her for that. After doing my own research - I've learnt that you can't change a depressed person, only learn how to support them.

Ever since I've been trying to be supportive, because I'm Narcissistic - this takes up all of my energy and leaves me in a bad state of mind and not feeling good( I end up depressed).

Please can someone help me with a solution to this frustrating situation? And no, I do not want to leave.