I need to run today, Wednesday, and Friday to be better prep'd for actually running this 5k saturday, as opposed to jsut pushing to get through it.
If the run is Saturday, I wouldn't run on Friday . . . maybe a brisk walk to keep the legs loose. You'll get more benefit from being rested and relaxed than from any training the day before (actually, you'll get zero training benefit from a run the day before an event).
Also, if you are running 2.2 miles at a sub 10-minute mile pace you aren't out for long enough to really build your aerobic base, which you need to do before you can improve much. You need to have your heart rate elevated for at least a half an hour or more to realize much benefit. Speaking of which , do you use a heart rate monitor?
If not, I'd recommend it. It helps a lot to know how much you are exerting yourself and also to learn how to pace yourself appropriately. You'll probably find that to keep your HR in a good training zone you need to slow down. Follow that guide, slow down, keep your heart rate where it needs to be and you'll find your training runs hurt less and you can go out for longer periods of time. Once you get the length (in time, not distance) of your runs up and you learn to pace yourself, you'll start to improve more quickly, both in terms of endurance and speed.
Another thing that most people skip is sprinting. At the end of each run (unless it's a scheduled 'easy' run) just plot out a distance of a 1/4-mile or so and run it at a higher pace than normal. Walk back to the beginning and repeat a few times. Use a stopwatch to time yourself, and don't overdo it - a couple of sprints is enough at first. The idea is to run faster than your regular running pace so you can get your legs and body used to those motions. You won't see the benefit right away, but you will see your regular running pace increase more quickly over time.
For the cramping, there are good breathing exercises you can do. My favorite is to push your belly out while inhaling and pull it in while exhaling. You may find some others work better for you.
Keep running man! Really, just a little bit of structure in your training will carry you a long, long way! You've already got a pound-for-pound advantage over me (I'm just over two bills), so when the BYOC Olympics hit next year, you'll be ready!