I was prescribed 80mg of Adderall a day and it wants working. I started taking 100mg to 120mg a day and just got what i needed from it a little. I have ADHD but also take it cause i work up to 15 hrs a day and have a young child at home. So i need the energy and to be awake without much sleep. But my doc switched me to Vyvanse 30mg since the Adderall wasn't working unless i was taking an extreme dose. I feel like that mg is gonna me to small. Will it be to small or will it do what i need it to do and why? Also i am 6 foot 7 and 400lbs. Will that affect it?