Ok first of all, I know it's wrong to abuse prescription drugs. This is the first time I'm doing so and it's out of sheer desperation and stress so please save me the lecture.

So yesterday, I started off by taking 27mg of Ritalin. I didn't feel any effects so two hours later I took a 18mg pill (snorted half, swallowed the other half) and it made me shaky but not focused so I took another 18mg one. So basically I had 63mg of Ritalin in my system yesterday (my first time on the medication) and it took hours for it to work. When it finally took effect, it made me euphoric (better than my Prozac's ever made me feel) and although I still kept getting distracted, it allowed me to study efficiently. It was great.

Today, I took two 18mg pills (so a total of 36mg) so far and nothing's taken effect. I don't have the same effects as yesterday and I have no desire to start studying.

Does anyone know why the Ritalin is having no effects on me even though I've taken such high dosages? (I've never even been on that high a dosage for my Prozac)