The first 5K

I did it. I tried the 5K. I can only say I tried because I didn't make my goal of running the whole thing. I do have some excuses prepared: I had a head cold for a week and a half, so I hadn't been training; I had only slept 3 hours the night before because Laura picked that night to only sleep 3 hours (?). But still, they are just excuses. I will try again and do better. I ran almost 2 miles at a much faster pace last night. I am going to sign up for another official one this fall to give me another goal.
It wasn't a total disappointment: I was glad to make it under 40 minutes (39:23); I came in 593 out of almost 800; It was very exciting to be running with so many other people; we were running through the zoo, so it was fun to see the animals watching us as we jogged by.
Can someone please explain how I can go from getting almost no exercise to running every 2-3 days for 6 months and still be officially "obese"? Actually, I gained 5 pounds? That is ridiculous. Just think how much easier each step would be if I lost 30 pounds. But I'm not giving up yet. I definitely feel better, physically and mentally, so it is worth every difficult, jiggly step.