LG: Your back.
It may not be "consistent" because you don;t yet know what makes it consistent. I'll bet you may be, for the most part eating healthy, but you may have a very high glycemic Index food that could be causing issues. A table of 100 is located here:
https://www.health.harvard.edu/dise...lycemic_index_and_glycemic_load_for_100_foods
White bread, sugar and pizza are killers. Your inconsistent highs may be due to a high glycemic index food.
Word of advice: See an endocrinologist.
A "cold" usually increases insulin requirements, but it can do both. A cold requires more careful monitoring.
Vitamin D and TSH (Thyroid Stimulating Hormone) generally are looked at.
A reminder or if you don't know. The red blood cell is responsible for glucose transport and they die every 3 months or so. Here's the bad part, if they experience a high glucose event, they get poisoned and then don't transport it as well. So, you could have three months of being tired until all of the poisoned red blood cells die. The hA1c or Glycosated Hemogobin is effectively a weighted average of glucose levels in the red blood cells, but not in the right units to compare to the average.
Good luck!