I don't think for a minute that lack of a carb rich breakfast would cause you to 'bonk' in that a short period of time. Your glycogen and fat stores should easily last you 30 miles, especially if they were topped off the night before. I have impaired glucose tolerance and bike long distances on a very low carb diet. So, I would look to another reason, perhaps a virus or other illness for the lack of energy on the bike. Also you can't 'bonk' in a mile, that is something that only happens after several hours of riding and fuel depletion.