For most cases of upper respiratory infections the upper respiratory infection clears up and goes away within 2 weeks.
The upper respiratory infection should clear up and you should feel better after a few weeks but sometimes it may take 3 to 4 weeks for some people.
If the upper respiratory infection lasts longer than a couple weeks though or the symptoms seem to get worse then you should see a doctor or go to the emergency room just to be safe.
The doctor may be able to prescribe you some medicine such as antibiotics and be sure to stay hydrated, use a humidifier and get plenty of rest and Vitamin C.
Stay home from work or school if you have an upper respiratory infection until it clears up.