I totally understand your concern. I used to get panic/anxiety attacks fairly often, and would avoid doing things for fear of embarrassing myself or being an inconvenience to other people.
First of all, you should be really proud of yourself that you are choosing not to avoid this trip. At the end of the day, it would be better to experience a panic attack on this trip than it would be to avoid it altogether.
What I've learned over the years with anxiety/panic is that it's 100% fueled by resistance. In other words, the more you resist it, the more intense the anxiety will be. Your nervous system interprets your resistance as you being in danger, which fuels the anxiety. It's an out-dated survival mechanism that used to be super useful when we humans were all living as tribes in nature, surrounded by wild animals and other tribes that wanted to kill us. In today's advanced world, though, 99% of the time it's a false alarm!
So how do you not resist it? It may sound strange, but you kind of need to train yourself to WANT to have a panic attack, or at least be completely open and comfortable with the idea of it happening.
Most of the time, when people feel their anxiety/panic starting to bubble up, they start thinking, "oh no, here it comes again. I'm about to make a fool of myself. Not now, not now, not now!" etc etc. THAT'S resistance, and that always makes things worse.
Instead, try to use it as an opportunity to be completely present. How does your stomach feel as you start to get anxious? Does you breathing get a little faster? Do you start to feel lightheaded? Be curious about it. Put yourself in the mindset of an extraterrestrial learning how the human body works for the first time. Try to will yourself into getting even more anxious so that you can notice even more things.
You can also try to egg it on. "Alright, let's see what this panic attack is all about. I want this to be the biggest one yet!"
By approaching it in this way, you will break the cycle. The only hard part about it is that it's so counter-intuitive to what we think we should do. If you truly practice this, though, you will see that the tiger living in your head is actually a harmless house cat.
Man I could write about this stuff for hours, haha. I hope this helps.