different meds | ADHD Information

Im on dex amphetamine, since Saturday, and have noticed I am not very hungry at all and have found that I have only been sleeping about 2-3 hours a night, but I still feel rested and dont collapse in a heap around 4pm as I used to do. Is this normal or should I talk to my Dr about changing meds.
 I am not unhappy with the side affect at all but being me everything that happens that is different from the norm I get concerned about. Thanks in advance for any help  I like to know what is going on in my life.