"If trees could scream, would we be so cavalier about cutting them down? We might, if they screamed all the time, for no good reason." J. Handy
If it were me, I would not run a 22 miler. I would suggest doing 20 miles at your own pace this weekend, and seeing how it goes. My first marathon, I was pretty bad about getting in the 10 or 12 milers during the week as well. Keep up those daily 6's and i'm sure you'll be fine. Do allow time for rest though, especially that first week in Oct.