I am also on the fence on how to handle Mothers Day. My D is not old enough for do something on her own, so it is tough. I had planned to give her something "from D" but I still don't know exactly how or what to do.
Might be good to poll the board on this...
BTW, I understand all the things you miss.
It is really just having that partner in life. "Don't know what you have until it's gone..."
BITS
Happiness is not something ready made. It comes from your own actions.