Sometimes the bad germs home right in on the larynx and we feel OK otherwise. Since you are feeling like you have a bit of a cold, it sounds like this really probably is physiological. Try keeping your throat warm with a scarf, do not try to talk or whisper as this does strain the larynx, gargle with salt water to kill the baddies, and drink hot peppermint tea with honey and lemon. That is a great drink for helping one's voice return.

Hope you feel better soon, tree.