i have a severe cough, wheezing, and white sputum (with a little bit of green/yellow discoloration). i was sick a couple of weeks ago, but the cough never completely dissipated. the sickness came back a couple of days ago, however, not as bad. I've been drinking lots of water, taking mucinex, dayquil, and nyquil... i feel a little bit better, but I'm still sick. what might be wrong?