Thanks for sharing your concern.Excessive salivation
is called sialorrhoea.
It occurs due to infection to salivary glands,any chronic irritation to your salivary glands might cause such symptoms.
some times certain drugs also cause similar conditions.Few bacterial or viral etiology can cause excessive salivation.
Are you taking any medication?
Here i would advise you to seek your dentists help and get your salivary glands examined thoroughly for the cause.
Hope it helps.