Change In Plans...
In our every day living of life, things happen to upset our plans. We have things planned, and have made arrangements for months - and with just a few words - BOOM!!! Our plans are altered forever!!! Sometimes it's an important event that means a lot to us - like a trip, or concert, a visit with an old friend, etc. Something unforeseen happens, and you're suddenly free for that block of time.
If it was someone's irresponsibility, maybe you need to take time to assess that relationship. Is it a pattern? If it is, what are you going to do about it? If it was the first time, you can express your disappointment, give them a chance to explain, and move on.
You have have to keep perspective, and keep your eye on what is important:
1) Sometimes, when things like that happen, it can open the door for something even better.
2) Maybe there's a lesson you're supposed to learn - or the others involved, and you just got caught in the crossfire.
3) I personally believe everything, good or bad, happens for a reason - but we may never know that reason.
4) You have to figure out for yourself where you go from here.
Life happens - it's how you react that makes all the difference. Sure, you feel disappointed; but did you die??! Not usually...
Have a good day, and be safe...