JP - you didn't indicate on the glucose test what kind they did. If they took blood, it was A1C which gives a number to reflect your blood sugar reading over time. If they did the glucose tolerance test where you drink a sugar loaded liquid with blood taken over a period of hours, that tests your body's ability to handle and metabolize over a period of time. Neither should be overly swayed by one weekend of eating. While not alarming, a higher than normal reading should be concerning. My A1C was a very modest .2 over the normal range and enough to throw me out until I lost weight and was retested. That very little .2 was enough to, technically, classify me as "pre-diabetic".
I know what you mean about the weight, though. It was kind of a shock when they said the same to me (Me?! I'm not fat - I'm big boned!). However, it turned out to be one of the best things for me. It forced me to re-evaluate my eating habits, my activity and lifestyle in general. I would not have done it on my own without the hard concrete evidence of all the testing as my wake-up call.
Good luck in your endeavor. Sounds like all you really need to do is tweak the eating, and you would be well on your way!