Well even though you ordered on the day pre-orders went live, by the time the retail stores had opened there were already pre-orders done online in excess of 1 million units. The 10/31 - 11/11 sounds right on par. But there is definitely a chance that could be moved up. From everything we've seen, those estimated dates are both floating and conservative. I started at 10/22 - 11/XX, then moved to 11/11 - 11/27, then back down to 10/2 - 10/13, and then I saw my device was actually shipped today.
It's a craps shoot whether or not you want to cancel your order and try your luck in-store. It's worked for some, but we aren't sure when the 6+ will be readily available in stores (most markets outside of major areas like New York saw shipments run out immediately without any restock). I'm personally glad I didn't cancel, and I would be willing to bet you'll get your order in October as opposed to November.
Just my thoughts.