antihistamines line sineoff and benedryl will help clear tthe sinus's. but also consult with doctor incase it is an infection of some kind.

check with a doctor on the dizzyness too incase you have an ear infection or other health problems possibly going on and if it turns out its anxiety the doctor could prescribe an antidepressant that also works for anxiety. it could also be that when you get nervous or anxious you start breathing faster so your body reacts like it would if you were hyperventalating. try relaxation techniques like trying to slow your breathing/heart rate. Relaxation music, and so on.