Taking forever to come up from lows

I automatically expect it to take 45 minutes to an hour for my BG to rise after a glucose tablet or any other quick-acting form of sugar. I will not take a second dose unless I drop below 50, when I would need a second table to cover the low. If I were to take 51 grams of carbs, my sugar would eventually rise by 250 mg/dl. So I really wait a long time.