Why is Adderall not effecting me anymore?

i was taking a lot of adderall over the summer of 2009. i loved it, it made me talk a lot, gave me energy, and i never wanted sleep or food. but i liked the feeling of focus and relaxation it gave me. that was the first and last time i had done adderall until now. i got a bottle of them 2 days ago. i took 2 at 1pm and im pretty sure it worked. i felt good all day and i cant remember if i slept at night(if i did it was only for like 3 hours). the next morning i took 2 and then another 1 about an hour later cause i felt nothing. 3 hours after that i snorted one. still didnt really feel much different(yes i now know that taking 4 like that is bad). that night i took a sleeping pill and crashed for 7 hours. next day i parachuted one in the morning. then took 1 more about an hour later. still nothing. why am i not getting the nice feeling anymore?