Surprisingly, I cope fairly well in stressful situations, to the point where other people think I'm calm!!
However in the day to day stresses of life, the internal chaos of my mind can be a nightmare. But still you couldn't really pick it from the outside. My anxiety is extreme but the symptoms are really internal. I feel like I'm dying but look completely normal to other people.
I think it's different for everyone, either way though, anxiety absolutely blows and it's extremely difficult to control even when you want to.