I have been seeing orange mucus since yesterday. i've had a cold for the last week. what could be the reason for it?

Rhinitis/sinusitis: If you are having orange discharge from your nose, this is rhinitis - inflammation of the mucosal lining of your nose. Usually it's a viral infection (common cold), which can also include sinusitis. It should get better with a tincture of time (and decongestants). If the sinuses become acutely painful or tender, and if fever, that indicates bacterial infection that may need antibiotic treatment.