I have been experiencing a slight cough, mentally fuzzy, headaches, weakness, tiredness for about 4 weeks. I went to a walk in clinic because my Dr retired 2 months ago and I haven t found a new one. I was tested for strep, mono, had an X-ray, and an ekg. All were fine, they took 4 vials of blood and I won t get results for 4 days. What could they be looking for ?