Be careful with not being able to breath. You can start to hyperventilate. Your muscles will contract, and literally scare the s**t out of you.
My doctor thinks my problem is my middle ear. My balance is way off. But is started with shortness of breath, which lead to hyperventilating and muscles contracting. Now I'm left with balance problem, pressure in my head, no pain just pressure, and nausea. Also extremely weak. Take is easy, and see a doctor.