Or it's just your personality. I could name a number of guys I knew back in college and even now who are just uninterested. They work, play video games, hang out with other guys. Theu see pursuing a girl as being just more time and effort than is worth their while. And I have a number of married guy friends who wish they had that carefree single life again. It takes all sorts to make the world...don't let society tell you that you have to be a horny male to be satisfied with life. By all means, get your hormonal level checked out if you are concerned but if everything is fine then just go with the flow.
F 28/5'4/100 lbs
"I'm not a psychopath, I'm a high-functioning sociopath; do your research."