Nightmares About Long Flights to Foreign Countries

A recurring nightmare I have is that I'm about to get on a very long flight to a very foreign country, very far away, but I'm totally unprepared: I don't have cash, I haven't packed anything, I'm wearing the wrong clothes, I haven't gotten any vaccinations, I haven't made any arrangements, etc. So we're getting on one of these very long flights pretty soon, and I'm starting to freak out a bit about it.