When you have a panic attack, do you get feeling of unreality?

Very Common. During a panic attack it is common to experience feelings of unreality or derealization due to physiological changes in our bodies caused by a sudden and unexpected release of adrenaline. Hyperventilation can cause changes in your bodies ph that leads to changes in sensory perceptions which the brain will interpret as unreal. Eventually the body will restore reality.
Can Happen. This can occur, especially if hypervevtilation is part of the picture.
Yes - Unreality. When one experiences a panic attack physiological changes occur in our bodies such as a sudden and unexpected release of adrenaline. This leads to increases in heart and breathing rates. When we breath too fast the oxygen and carbon dioxide levels in our bodies change causing feelings of unreality. Other sensory systems, such as vision can be affected, contributing to the feelings of unreality.