I have no idea what it could be...
I do know however, that the human body release fluids everywhere. Where ever there is an exit, fluids will go through them. Sometimes to prevent infection, through emotions, or just the body cleansing itself, etc.
Like tear ducts, and tears
Like mouth, and saliva
Like his/her special parts, and urine.
I would strongly advise that you see another doctor, if you feel that he/she doesnt take your concerns seriously.