I agree with Pipkin again
That sounds more like a very hightened anxiety level that you're feeling, as a panic attack wouldn't be able to go on for that long. Of course, you can have a panic attack which goes down and then come's up again, but it wouldn't be one long panic attack hun
I also agree with Pipkin on trying the propranolol before you go away. Get used to how you feel when you've taken one, and whether you find it helpful for you or not. That will also give you time to get something different if you find that you're not keen on it. I've never looked back though, I find it so very helpful with the physical symptoms of a panic attack and that, in itself, gives me more confidence