All I saw was "pancakes" and I was soooo reading this thread!
My enemy with pancakes is the butter and syrup. If I eat them before a ride I always put fruit on them. For some reason the sweet makes me feel terrible (and I use sugar free syrup). Go figure!

Who knows what it was??? Maybe just a little stomach-memo to tell you to slow down for a bit and digest a little more?? Regardless- glad your ride turned out GREAT and that you pushed it through the tough parts! Good for you!!!!