The thing is, unlike high blood pressure, low B/P is defined primarily by signs and symptoms of low blood flow and not by a specific number. Some people may have a B/P number of 90/50 with no symptoms and therefore do not have low blood pressure. However, others who normally have high blood pressure may develop symptoms of low blood pressure if it drops to 100/60. For that reason, doctors often consider chronically low B/P too low only if it causes noticeable symptoms.
Yes, low blood sugar could be a cause of the low B/P, but there could be a whole host of other reasons too. Then again, it could be nothing at all.