Instead of riding 30 as planned, I stopped at 10 miles out and sat in the shade of a tree in a park, drinking a cold Coke and eating a food bar and trying to collect myself. Reversed and rode back home.
Not a disaster. Didn't bonk, but flirted with it. Felt like I had overtrained, except I'm not training and I'm not riding long. Maybe a day off is in order.
OTOH, it was a beautiful day. I saw a few cyclists out on the local roads and that doesn't happen to often. Drivers were extremely courteous. A great day for a ride.