I have to say I feel a little like you this year.
I have two adult DD's. Neither of them live at home. I have had Facetime calls this morning individually from each and both of them said 'Happy Mothers Day' first before we continued with our chats.
However I have had no cards, no flowers, and no gifts.
My DH hasn't mentioned anything about it so its just a normal day here and I have just been sat here, thinking about my own Mum, who passed away suddenly a couple of years ago, and how much I loved Mothers Day because it was my chance to spoil her a little, to say thank you for everything she does for me, and to show her how special she is.
I also went on Facebook and saw a post from friends of ours gushing about his wife and thanking her for being an outstanding mother to their children. My family have never been 'facebook gushers' and neither have I, we just don't do that kind of thing. However I found myself feeling a little sad and unappreciated today although I know its silly. I know my girls love me, and I know my DH loves and appreciates me. I guess its just nice to be told sometimes and to be made to feel it.
I have just been on Amazon and ordered myself some pink prosecco and chocolates to arrive tomorrow.
Happy Mothers Day OP and to all other mothers feeling a little underwhelmed today.