Excessive Saliva In The Morning

hi there, i m 23 years old and i have the excessive saliva problem for the past 5, 6 years. I brush and floss every morning and night and rinse my mouth everytime after i eat. when i am awake every morning, the saliva will start to gather in my mouth, it usually has a very stinky smell too. the only way to get rid of it is to get up and brush my teeth. some time if i am really tired, i would try to keep my mouth shut to prevent it dropping onto my pillow, but usually it will eventually builds up and i am forced to get up to brush my teeth. have been trying very hard to look for a solution. thanks in advance.