Well I did have a similar experience, but I went in the other direction. I was 240-250 lbs when I was 16 years old and only 5'6". I never had a problem with friends but I wanted chicks badly. I was sick of being the "fat funny kid" that everyone compared to Chris Farley. So I did something about it, much like you did. I started lifting, playing basketball, cleaned up my diet, and before I knew it I was 180 lbs. The working out went on for a good 6-8 months, and one day (I don't remember what happened) it just stopped. For a long while I maintained the weight without working out (I'm a meso) and I even hit another growth spurt at some point (I'm almost 5'10" now.) It never really dawned on me that I was slowly but surely putting the weight back on. It took almost 5 years but I weighed myself one day and I was 210lbs. The heaviest I had been since I dropped all my weight. It took alot for me to get back in the gym. I knew how hard it was getting back in there and getting started again, but it was a priority. As hard as you worked, and as much as you accomplished, it just doesn't seem that working out is a priority of yours anymore. Unfortunately sometimes it takes a life altering event to make the nessecary changes. I realized I was on the fast track to obesity so I did something about it. As much as you enjoy being big and in shape, it's something that you and only you can control and make time for. You said it yourself, there is more to life than being big and strong, but now you have to do some soul searching and figure out exactly how much it means to you.
I hope my little story was of some help to you. (Although reading back on it I'm trying to figure out my point. )