I agree. You know what Prednisone is? I was in the ICU with serious lung problems and I was on Prednisone. Surely you at least have Bronchitis or Pneumonia.
He gave you prednisone for a cold? I would think that 24 hours is time to get it out of your system but it would be better to ask the Pharmacist at your drug store, and certainly enquire about the prednisone maybe the Doc thinks you have something aswell as a cold?