Upset

Liz
So my mother is a teacher, and lives across the country, and I am her only daughter. I have had 3 babies and this will be my 4th and This one is my first summer baby so she is finally able to be at one of my baby's births. I was very excited to have her here for the birth and planned on having her in the room with me since she said she would come as soon as I said I was having the baby and thought she would be excited too. However, I just found out she and my dad scheduled a vacation the week before I'm due and didn't tell me this until I was 36 weeks along and she then told me that she wouldn't be coming until after my due date no matter what. I know I might be over exaggerating the situation but I'm really upset that my mom just doesn't care about being here. I haven't said anything to her about being upset. Should I just let it go or should I tell her how I feel? Im afraid if I tell her how I feel it will just make things awkward and weird between us, but it really upsets me that my own mother just doesn't care at all.