Awww, Sleepygoat, I know so well that upsetting feeling not knowing if she will show up or not. Even today, if a person is supposed to meet me somewhere, I feel my stomach churning if they are not there right on time. It's become a PTSD thing with me that I can't seem to shake. My bottom was a night that my son wasn't on a bus he was supposed to arrive on and I drove over an hour to a crackhouse to find him...stupid choice on my part but the point where I surrendered it all to God.
Maybe have a Plan B ready, so that if she doesn't show up you have something wonderful to do for yourself. Whether our kids acknowledge it or not, we ARE great mothers and can celebrate ourselves if need be.
Sending big hugs, and wishing you a Happy Mother's Day.