Time to "just do it"

I did the 1/2 MMM last year, which was the first time I ran anything in my life, and actually went on to do full Marathon in Houston in January, but hurt my knee (and also got a little burned out) and almost completely quit running in the last 6 months. I'm sorry to say, I have become again a couch potato, I'm out of shape and fat. So, here I am starting to train again, and it's very much harder than last year. Last Sunday I got myself together for an afternoon run, I picked a course I used to run all the time. Hey, I used to do 6 miles easy here! But I'll only do 4 this time, I thought. Well, I can be a real idiot at times. It was a hot afternoon and after about 1.5 miles I started to feel nauseated and remembered I had had a hamburger for lunch only about 90 minutes earlier. I could really feel the extra pounds I've put on, in fact, my stomach seemed to stick out in front of me as I ran, and sort of took on a life of it's own, bouncing up and down like a meaty beach ball. At about 2 miles I started getting dizzy, thank goodness I brought a bottle of water which I drank some of and the rest poured over my smoldering head. That's when I started walking, and felt better and jogged a little to finish it out, but the 4 miles took over an hour. I felt like quitting right then and there. But later, after the sweat dried off and my mind began to clear and my stomach stopped quivering, I felt like I had really done something worthwhile. Even though it was hard, I did it. I guess I'll keep trying.