I'm so sick, what could it be?

On the surface, this sounds like a respiratory infection.  However, so many things determine what (if any) tests are needed for diagnosis and what treatment should be started.  You will need to see a physician who will ask about your age, medical history, medications, allergies, smoking hx, and other symptoms.  The physician will perform a physical exam to help determine the diagnosis.  You may need other tests, such as an xray.  Therapy will be determined by the careful weighting of all the involved factors.  If a new condition such as this affects your life in the way you describe, you need to see a physician.  Best wishes as you pursue this.