CFM, I would think the odds of this being the problem would go up if you are especially light and/or you had relatively high pressure in your tires. But, like you say, it may be difficult to ever really figure it out.
I hope today was better than yesterday for you and I hope tomorrow is even better.
Oh, and by the way - I was stung 8 times by a swarm of bees today (totally non bike realted), so I'm feeling a little of your pain tonight.