Not knowing where your daughter is must be agony - and it sounds like you are still grieving - I think if someone goes missing, it must be even worse than someone you love dying (and I am not being disrespectful, in saying this !).
I think Mother's Day as with any calendar anniversary i.e. christmas, easter, father's day etc etc - are just commercial hype - we can all be good, kind and helpful to our family any time of the year - I know people who buy a card, chocs or flowers for their Mum, but never see them for the rest of the year and never give them a helping hand.
Just view tomorrow as just another Sunday, silka, but I am sure wherever your daughter is , she will be thinking of you.
luv
Denise x