Unhappy day

Right now I am unhappy because I get to know that I need to fly for business trip purpose this weekend. I am damn unhappy because I thought it was next weekend. I am not sure it was my understanding problem or my boss. But I believed not my problem. He received his email this morning saying that asked me to be prepared to fly on next weekend. So, I am okay with it. But just now I received someone's email regarding my next project meeting and my boss writing an email to those that involved for the plan on next Wednesday. So I started to feel weird and emailed my boss again to confirm when will be flying by giving him the dates. And he replied this weekend which is 21st. Wth. This week and next week also can't differentiate it. I am superb unhappy because of this. :(