From Wiki:
"The prevalence of this condition is difficult to ascertain and controversial, because a number of stricter or looser definitions have been used, and because many healthy, asymptomatic people can have glucose tolerance test patterns said to be characteristic of reactive hypoglycemia.
For diagnosis, a doctor can administer an HbA1c test to measure the blood sugar average over the past 2-3 months. Additionally, a 6-hour glucose tolerance test will chart blood sugar during the past six hours.
According to the U.S. National Institute of Health (NIH), a blood glucose level below 70mg/dL at the time of symptoms followed by relief after eating confirms a diagnosis for reactive hypoglycemia."
With that said, it would be in your best interest to schedule a full health evaluation with your doctor. If you happen to dip below 60 mg/dl it could be detrimental to your well being.
However, I would like to comment that your bloodsugar usually being in the 80 - 90 range is completely and totally normal.
Truely normal blood sugar doesn't go above 120, becuase your pancrease has very fine tuned control to keep your blood sugar optimal.
Frequent levels below 60 is not so good, if this does happen. However, it can be managed by eating slowly digested copmlex carbs rather than very sweet foods which will be digested quickly. Always eat some fat and protein with your carbs as this will also slow digestion and make sure you sugars stay where they should be in the range of 80- 90.