It does hurt, and Ts know this. If a T does this all the time, then they need a new system, and maybe you could go to a definite time slot each week.
The main thing to remember is that it isn't personal.
Yes, other doctors and even friends have to do this, reschedule appointments...and if it was for something you felt important it affects you more.
You are right, things do appear larger than life when it concerns a T appointment...perhaps it's because it is the place where you know you are listened to and understood, and accepted.
If you are able, then you might consider calling the T's number to verify your appointment. But I prefer the "standing" appointments (same time, same day) if both of you can do that.
I'm so sorry this happened to you.