Haze, Ihave experienced this all my life. If I eat a high carbhydrate meal or snack on sweets I know I can expect to end up eventually sweating profusely, shaky, nervous and irritable. I must then eat a snack of mixed carbohydrates and protein to feel better. I've never been diagnosed with hyperinsulinism but I feel sure my pancreas overreacts when I've digested a high sugar load.
I have no clue what my actual blood sugar is at the time. I am just acutely aware that this can and does happen to me very, very frequently.