Careful with caffeine before your driving test

Drank quite a bit of energy drinks before my exam today thinking it would help me focus, instead my left leg would not stop shaking for 80% of the test. I tried planting my feet to stop it from shaking, then tried to move off in first and stalled. Still managed to pass, not sure if this was insane nerves, the caffeine I drank before, or a combination of both. But thought I should maybe make people aware.