I have been taking vyvanse for about 5 years now. The first couple years I was talkative, I felt normal. Now the years go on and I feel like now when I take it I lose my personality. I wake up early at 7 and work from 8 to 5 every day, by the time its 5, I feel very drowsy, tired, no motivation, not talkative. Could this be an issue due to vyvanse? Or could this be an issue to drinking a lot of coca cola every day? One more question. I take 60 mg of vyvanse and I drink about 3 20 oz coca cola s a day, is this bad when on vyvanse?