Replying to Concerta FAST!

Ok ive got tons of exams and papers within the next week, some already overdue. basically I am fucked! I can't get my hands on adderall but i do have access to concerta. I haven't been diagnosed with any attention disorder but I have a god awful time focusing. Im going to go get some within a few hours so i need replies fast.

Will Concerta help me focus better (my friend claims it will do the opposite if I dont have ADHD)? how does it differ from Adderrall? How much should I take? Any other the tips? Thanks.