Adderall XR 30mg Question?

I do not have ADD or ADHD but i do have trouble focusing. Today i took a 30mg XR capsule in the morning and it helped me to focus unbelievably...so much so that i plan on taking one every morning before school., My question though has to do with the little kick that it gives lol. After about 2 hours i was feeling pretty awesome..not euphoric or anything even close, but a noticeable feeling of overall well being. How long will it take before my body develops a tolerance to this, and i no longer experience the mood enhancement that i felt today? Also, does the mood enhancement have anything to do with the drugs ability to make to focus? Even in the absence of mood elevation will it still maintain its powerful focussing effects? Thanks!!