What made you think you were bonking?

If this ride took you under 3 hours, it's very unlikely you were bonking. You have enough stored glycogen in your muscles to run your body for approx 2 hours. You ate enough to last another 2 hours.

Answers:
1. No idea if you were bonking. Describe your symptoms. But probably not.
2. What you do is going to be different than what I would do, because of differences in our levels of endurance training. How many miles per week are you riding? Just the one ride per week? The more training you have, the less you will need to eat. It also depends on the intensity at which you are riding. Less intense, slower rides allow you to burn fat as a calorie source and your fat supplies are almost infinite for the purposes of cycling. Your training rides are an opportunity to train yourself to need less calories. My personal eating scheme is nothing for the first 90 minutes, unless I'm on a really long ride, like 100-200 miles, or I'm going semi-long maybe 50-70 miles but riding intensely, in which case I start eating right away. I eat 200 cal/hr of pure carbohydrate (Cliff Shot Bloks because they're packaged perfectly and easy to eat while cycling), plus another approx 50 cal/hr of electrolyte drink (I use Skratch Labs). On a short ride, 3 hours or less, I might not eat anything unless I felt hungry.
3. I would personally keep increasing your long ride each week by 10%. Then when I got to 45ish miles, I would just keep repeating that length of ride. The more time you spend close to you event distance, the better it will go. One week prior to your event, I would taper by cutting volume in half, but keeping intensity the same. The exact details of how you do this is probably not hugely important, but I'd personally be off the bike 2 days before the event and ride an easy hour the day before.
4. You are not over thinking this. Confidence comes from experience, practice and preparation.