Improve, improve, improve! By all means!
I think that is a great attitude. Now that you have your wings back, see where they can take you.
Since you mentioned the gym and diet, though, I think those are two areas where it really is a long-term game, where being consistent and just sticking to your plan is the most important thing. (it's kind of similar to sobriety, I think, so shaping up fits well to new sober life) Plan the work, work the plan, assess progress in quarter-year intervals. Long-term stuff. It's nice because it's all you, you're not dependent on anyone else, it's just success or failure based solely on your actions. A great opportunity to build up some self-confidence!
Oops, sorry, I got on my fitness soapbox there for a minute . .