I had the exact same fears as you about having fun and socializing. And the exact same result as Sugarbear. I have way more fun now!
You know how when we're drinking, we sometimes think we're the funniest, smartest person in room? Well it turns out, when everyone except you is drinking, you really are the funniest, smartest person in the room.
I've been on this site for about three years, and never heard one person say they regretted quitting. You're going to be really glad you did this!