Hi.. Thanks for the query.. The discharge of yellow and thick mucous from nose is most probably due to infection in the sinuses leading to Sinusitis and as the sinuses drains through nostrils, therefore fluid/pus accumulation in sinuses can drain through nose.. It can happen secondary to severe cold and upper respiratory tract infection.. So I would suggest you to consult an Emergency room and get evaluated and a thorough clinical evaluation and investigations like PNS view x ray can help in diagnosis and treatment can be done accordingly.. You can be advised a course of antibiotics, anti-inflammatory painkiller like Ibuprofen, decongestants like Pseudoephadrine, do saline nasal irrigation, steam inhalation and use a humidifier in your room.. You can also be advised decongestant nasal sprays containing Xylometazoline or Oxymetazoline.. Avoid spicy and chilled foods.. Do warm compresses around nostrils.. Hope this helps.. Regards.