Yeah that's normal. If i ever have a panic attack in front of other people I usually just attempt to get out of the area without attracting attention... It's not always possible,but it's usually the best I can do. If I can't leave then the people around me try to help(usually friends or family). Usually when they try helping it makes it worse. Hearing things like "you need to calm down" or "don't worry about it" or even a simile "are you ok?" can, and usually do, make my panic attacks worse. I can tell when i'm about to have a panic attack but i can never describe what it feels like..
I always feel shakey just before, during, and after the panic attack. if i ever notice i'm shaking i will usually have a panic attack soon. When it starts to get out of control, Shaking is one of the first symptoms of anxiety i get. I guess it's nice to have that warning, to get out of the area or away from what's causing the stress(if you know what it is, that is. Half the time i have no idea why i'm having a panic attack..). I still hate it, though. Once i start shaking, it's obvious to everyone that something is wrong.