8.1 is really just on the edge of being diagnosed. The massive sugar load for the test often tips woman over the edge for a positive, when in real life they would never eat that much sugar in a hit so it wouldn't be an issue itms.

Even the 7.4 you got after McD's isn't actually high. They make the limits for GD very tight but in reality anything under 8 or 9 is fine for after a meal. Even fasting results they don't really care until it is over 6.

Personally with those results I would consider it a false positive. Either ask for another test, or just monitor for a few weeks and then if you have no unaccountable highs ask for a reassessment of the diagnoses because it will affect your birthing options.