Nick, are these places in the order you visited them (on your list)? If so, wow, you were all over the place! I've been to some of the places you visited this summer, and wonder if maybe we passed each other on the road and didn't know it!
My bet is you'll be ready to go again soon, as soon as you rest up. I'm 51, and the wanderlust never leaves me, although I am always happy to be home when I get there.
Don't worry too much about getting older though -- you youngsters don't have a lock on physical activity. I have a hike planned to the bottom of the Grand Canyon this December, and I do not expect to be carried out. In fact, the last time I hiked it, at about age 48, only one person passed me on the hike out. I made it out at the same speed I hiked down (the norm is a 1:2 or 1:3 ratio). Age is not prohibitive, as long as you work at it and stay active. Bob