Nothing makes a heavy drinker or alcoholic more uncomfortable than being the only one drinking at the table. it puts their own habit on the spot. I know I always changed my order from beer to pop if my date didn't want a drink.
As others upthread have said, in general relax and don't let people's opinions bother you, but if some of your friends are very inconsiderate about it or go so far as pressure you to drink, then consider that they may not be a good influence or friends worth having