Hi.. Welcome to HEALTHCARE MAGIC. I have gone through your query and can understand your concern.. As per your query sinus pressure does not seems to be due to antibiotics but many a times there can be sinus infection after extraction of upper jaw wisdom tooth due to close location of the roots of the tooth to the sinus and in case if the sinus floor perforates during extraction or there is any portion of the root of tooth slips into sinus there can be persisting infection and it can become worse during cold and flu due to increased congestion.. You should consult an Otolaryngologist and get evaluated and a thorough clinical examination and MRI or PNS view x ray of sinuses can help in proper diagnosis and treatment can be planned accordingly.. As of now you can take decongestant nasal sprays and also do saline nasal irrigation, steam inhalations and warm compresses over the areas both sides adjacent to nose.. Hope this information helps.. Thanks and regards. Dr.Honey Nandwani Arora.