Missed my coaching appointment

I completely forgot about my private coaching session I had booked for this morning. It wasn’t until I got to work and checked my emails that I realized what day it was and felt disappointed when I realized I’d missed my session.
I have plenty of circumstantial evidence as to why I missed it but none of those are really going to help me figure out why I missed something that I was reminding myself of earlier this week and consider very important to my life and to my future self.
When my life gets busy and when I have a lot of people staying at the house, I allow other people’s lives to take over mine.  I drop the ball in doing what I really want to do.  How do I show up for myself and keep focused on the things I’ve decided are important to me?