Getting back in shape after the flu (or whatever it was) has really been a challenge!! I have struggled to just run for 2 straight miles without stopping to walk for a minute. I know I can get back, but it is really hard for me, and is going slow. I'm in my 40's, I'm a new runner, and there is no such thing as quickly bouncing back.
I'm already a slow runner as it is, and even when I am in shape, it can be frustrating to read about a runner going for a "4-mile easy" run, or to read a training schedule and see that you are supposed to do an "easy 3-miler" on Mondays. There is no "easy" run for me! Not even a 12-minute mile is easy. A hard run for me is at a 10-minute mile pace - and that's when I'm in good shape. There's been a few times that I've been able to run a mile in 8 minutes, but never 2 in a row. Walking is easy. Not running. Not jogging. Every run is a challenge. Every mile is a challenge. But I just make up my mind to do it, and like Nike says, "just do it." That's the only way I ever managed to run the half-marathon (13.1 miles) without walking last year. I did it then, and I'll do it again.
Some runners say that all people are born to run. I disagree. There's no way I was born to run - but I really do enjoy it. That said, I am proof that even someone who has not been born with any talent or natural inclination for running can still fall in love with it, and be a runner. Put your mind to it, and if you want it badly enough (and are physically able), you can be a runner too. I will run as long as I am able - even if it means I slow down to a 4mph pace when I get older!