This happens to me a LOT. I'll be fine riding or running, and halfway home I'll feel like I'm going to pass out driving. Or I'll stop somewhere on the way home and nearly pass out walking around somewhere.

Is there such thing as a "delayed bonk" ? I always just chalked it up as a natural reaction to lots of exercising but I guess maybe it isn't. It hasn't happened so much lately but I've also learned that grabbing a soda on the way home can keep it at bay, which isn't really a healthy solution either.