Learning how to socialize and have fun without drinking? That's a complicated question. I think, first, you have to redefine the term "have fun" because it ain't gonna be like it was. There was NOTHING I didn't do socially as a drinker - so when I cut drinking out of my life, I cut my most of my social activities off as well.
I built new ones. It's not an easy road and it takes a while, I'm just 10.5 months sober and am only beginning to feel okay about my social life. But, I would have died if I didn't take this road, so it's worth it. Are you ready for a commitment to sobriety? Are you ready to even face that question?