Excessive saliva preventing proper speech? I say sh instead of s and kh instead of sh!! help me!!?

When i say, or 'try to' say/pronounce the letter s i say sh and when i say the letter(S) sh i say kh =( This is soooooo embarrassing to the extent that i'm rlly shy and don't like to talk alot. Is this related to my excessive saliva production? How do i reduce it? I'm going to a dentist in a couple of days. Can he/she do something?