How intense can panic attacks get?

It's possible. It defiantly sounds like one. Physical symptoms can sometimes manifest if your emotions are running that high, and they can be severe. I think it was a bad panic attack, and maybe with the elevation some motion sickness along with it. I am not an expert but I have had panic attacks not as severe but my friend has so it is very possible. I would check with a doctor if you are really worried, and if it is a panic attack then seek some help with medication if it's that bad. Good luck!