I have been taking adderall on and off for a couple of years and this is the first time it didn't work

I have been taking adderall on and off for a couple of years and I have never had a problem with it (besides the normal side effects) but when I went to college I notced my tolerance going down alot and I have been trying all the suppliments everyone says to try but it's not working. ANYWAYS I HAVE MY FIRST MIDTERM TOMORROW and I look one 30mg XR and one 15 IR per usual and for some reason it did'nt work. I feel naucious and dizzy and out of it my head hurts my chest is tight. The only things I did differently was drink a coke before taking them, and also take an extra strength excedrin and a calcium pill. What is going on????? I need adderall I can't focus without it, but its killin me.