What the heck? Adderall xr?

I'm prescribed the drug, I took it about 9 am this morning, I have a huge midterm tomorrow, at around 5 pm I was falling asleep like crazy, and I was so completely not concentrate the least. So at 8 pm when I almost dozed off studying I decided to get an energy drink, I drank it and immediately woke up, which is an effect I usually never have with energy drinks (I used to drink 3 large ones in desperate times and 0 effect) but like an hour after that, after I finished the whole drink and had a bite to eat (bread) my heart started pounding, and when trying to walk my calve kept cramping in such a weird way, and my fingers in my left arm got tingly (it comes and goes now). It's been well over 14 hours now, my heart rate is upwards of 100 bpm what the hell?