I don't like to say I quit, but rather my career came to an end after college. I wasn't super talented, but I worked VERY hard. I went as far as to move to the mountains for a summer and train at altitude before my senior year. During that year I averaged right at 100 miles a week, with most weeks being 105-110 and every third week at 90-93 miles with a day off. I ran a respectable 24:33 8k and 30:11 10k in xc. After XC I only ran 2 indoor meets, a 8:33 3k and a 14:27 5k off of no interval work, just base training, strides and some long fartleks. I suffered an injury, which I had promised myself if I got another big injury during college I would then be done.
I loved running in college. Sure it had its ups and downs with injuries etc but I had a blast and trained my ass off to be the best I could be. I wasn't a total running nut, I still partied usually once a week or at least once every 2 weeks during the season (but nothing too crazy) and during the off season partied pretty hard. I had fun.
I graduated just over 2 years ago. I do not miss it at all. I left the sport behind knowing I had accomplished what I wanted. I still get excited when I see old pictures and stuff, but that was then, this is now. I'm now in the military so I'm required to do a little bit of running (lets be honest, it's a joke) but other than that I rarely go out on runs just for fun. Now I enjoy my extra free time to do other things I enjoy without worrying about when I'm gonna get in my run for that day, etc etc.
Some people will run for the rest of their life. Some people will ALWAYS be chasing that next PR. Some people will continue to miss family functions because of training or racing.....and that's fine, but it's not for me any more.
Either be at peace with your decision or continue to run. It's not that big of a deal. I don't realize why so many runners are so crazy about if they run or not. Runners really are a strange breed of ppl!