You are experiencing depersonalization/derealixation. Its your body's defense against being stressed over a long period of time. The nauseas and dizziness is probably another symptom off your anxiety. Although you will find great advice on this site nothing beats seeing a doctor.
As for coping with your symptoms first know that derealization cannot hurt you, its actually your brain's way of resting itself. Just try to stay calm and keep yourself busy. A little meditation wouldn't hurt either. But first and foremost share how you are feeling with someone close such as a parent, spouse, close friend, and/or doctor. They will be able to help you more than you know. Peace and Blessings!