Question for someone who understands bloodwork

It depends. I'm not an expert, though. A1C measures an average over approximately a 3 month time period, so that heavy sugar just might affect your number a weeeeeee bit.

Then, it depends on if your doctor asked for fasting or non-fasting.

Not having sugar for 48 hours would probably not really affect the numbers. If it is fasting, it is measuring your glucose level after not having been fed any type of food for at least 12 hours. If non-fasting, it is measuring gluclose level on a typical day for you.
Your body's inslulin is constantly adjusting to your current condition, food, carb, no food, protien etc.

I wouldn't worry about if. If they are concerned with one day high, they would probably go ahead and do a A1C to see what your average is.

Not long ago, my sister had a reading of 37. We told her she would be dead if it was that low. She pulled it up on the patient portal and sure enough the reading was 37. Why in the heck they didn't catch that and have her redo the blood work. We did encourage her to call the doctor's office and inquire about it. They had her redo the blood work and she was in the okay limits.  Hopefully, your's will be okay as well.  But, you have mentioned being so wore out from some illnesses, so definitely don't rule out the oppostie of diabeties, and the is hypoglycemia, which can make you very tired.

After 48 hours, your glucose should be returned to the normal level for you. Your A1C is a measurement over 6-8 weeks. If you had that test as well, one week would have an impact of about 1/6 of your reading. That doesn’t mean that you would be 90 normally and then be 105 with your treat week, but that the reading would take into account that one most recent week.

Also know that it isn’t just sugar that will affect your levels, but your overall carb intake offset by your protein, fat, and activity levels. So if you spent that week at the beach or the zoo, the higher activity level could have helped a lot. 

DH had a physical the day after my mom's birthday dinner. We had lasagna, bread, cake and ice cream. Let's just say he had to go back to have it redone because his level was pretty high.

You should be fasting after midnight before your blood draw. Some say 12 hours, but that's a bit extreme. That will give you an accurate picture though. But don't go out of your way to try and "fool" the numbers--if you're diabetic, you need it addressed.

You don't need to be sugar free for any more than 12 because you want to see what your body is actually doing on an average day.

Some people will never have a "normal" fasting, I'm one of them. My liver will release glycogen if I get lower than where it likes my body to be (I think it's called something like dawn phenomenon) and I'll never be below 100 on a fasting, though I'm technically only "pre-diabetic" according to my A1C.

if your blood sugar comes back too high, they will repeat it anyway.

The last time I had to have fasting labs I actually ate a couple pickles, a hard boiled egg, and a piece of cheese (not on purpose--I was on my way home from work and had totally forgotten about the appt) and my fasting blood sugar was the best ever. Ha. I don't recommend that approach though!

Also I lied to the lab girl because i didn't want to reschedule. I figured I would come clean to the doctor if there was a need. We were already doing my a1C so I didn't worry about it too much. Jerk nurse move 🤣