My before dinner reading was 6.2, and my after dinner reading (1 hour) was 5.4. How can it be lower than before I ate...? For reference, I had a 6 inch sub and some water.
I assume you are not on insulin but did eat a tonne of high carb food in which case your pancreas had to pump out a load of insulin in a hurry which then drops your sugar low at which point you start to feel hungry again.