Caffeine overdose? It's like you gulped 5 espressos in one sitting! Man, that's totally reckless of you. If you're that worried, go to the hospital now.
The jitters is a symptom of caffeine overdose and so is the high blood pressure. Run, jog, jump on a trampoline. Expend all your energy. After a couple of hours, you'll still be awake. Watch a movie marathon while on a stationary bike. Don't forget to rehydrate (drink water) now and then. Water, plain water, is your best friend at the moment. You need to dilute the caffeine in your system and flush it out. If you feel like peeing, do so with gusto. It's working. Drink lots of water again afterwards. If you feel your heartbeat is still rocketing upwards, you really need to get to the hospital fast.