Hi..
Welcome to HEALTHCARE MAGIC.
I have gone through your query and can understand your concern..
As per your complain dripping of water droplets from nose,phlegm in throat or 
post nasal drip and bad smell from nose are all inter-related problems and seems most probably be due to 
sinus infection also known as 
Sinusitis..
You should consult an Otolaryngologist and get evaluated and athorough clinical evaluation along with PNS View or MRI of the salivary glands can be diagnostic..
If sinusitis is confirmed he can advise you antibiotics like 
Levofloxacin, steroid nasal sprays, saline 
nasal irrigation, steam inhalation and in case if there is congestion decongestants oral as well as nasal can be advised..
Steam inhalations with a few drops of eucalyptus oil in boiled water can help in refreshing your breath..
Hope this information helps.
Thanks and regards.
Dr.Honey Nandwani Arora..