I'm sorry that you are unable to experience the joy of the season. Please do realize that it is the depression, and that they Reason for the Season remains, and can comfort you even in your distressed days.
It's important to try and look forward, not back, to find life. Depression tells lies and makes you look backwards seeing only the negative. Yes, there are many negative things in life to view or review if we really want to ...and I know it's difficult to try and "have" hope when you don't have any due to depression.
Yes, it is, in a way, just another day. Do your best, God knows where you are, and why.