Is it normal to not be constantly looking for your next boyfriend/girlfriend?

Ok, so I'm 24 and I've been single since high school. I haven't been abstinent, but i have been single. Most of my friends are either married, in a relationship or have someone they regularly see. I've never been interested in a formal relationship. All my married friends are miserable. The problem is that people don't leave me alone about it. They are always playing matchmaker, questioning my sexual orientation, wondering if I'm depressed (I'm not), or think there is something wrong with me. It's irritating. IIN?