Hi,
My daughter (15yrs.) takes Concerta and prefers it over regular methylphenidate (Ritalin) because it lasts longer. As far as I know, Concerta comes in dosages of 18 mg, 36 mg and 54 mg...so I am curious about the 20mg Concerta that you are taking. The Concerta that my daughter takes is a pill, not a capsule. An 18mg Concerta pill is similar to 3 doses of 6mg of methylphenidate released over the course of approx 12 hrs.
Good luck at college!