Depressed?

I sit here wondering could it be that I'm depressed or just depressing? After the last month I've had I suppose no would blame me but I still feel a deep rooted sense of guilt for not being on the top of my game. Christmas is not the easiest season to be suffering the effects of grief.
I try to be supportive of my family but find that encouraging these relationships takes more energy than I have at this time.. I hope it gets better soon and that they can forgive my inability to interact at this time.
I used to feel like I was witty and even sometimes amusing but I find it hard to find something to laugh about.. I feel guilty feeling so horrible over what some would consider a small thing compared to the trials in their lives and yet I feel the same way about other people complaining.
I realize the irony in complaining about the hand I've been given while feeling anger and frustration when I see people complaining about their trials and tribulations which seem so minor and trifling compared to mine. Even the knowledge that it's a big deal to them doesn't make me feel any more compassionate. The last time this happened to me I remember my explosive rage..this time it seems to be more of a slow rolling boil. The anger never fully goes away.