Morning Hon. You need to test again. Anytime they are running that low early in the cycle, you need to be testing at least every hour, if not more.
Dose is not determined by the preshot readings, it's determined by the nadir, the lowest point in the cycle. At the rate he's going, you may need to reduce his dose anyway.
Mel will be back soon to help you out, until then, get another test. Do you have a higher carb food in case Cupcake goes too low? You need to be keeping a closer watch on him today.