Im having extreme loss of apitite and excessive weight

Patient: Ive been diagnose with ADHD and on pills that i just started this week (vyvise). My appetite is compleatley gone and i usually will only eat half a banana a day,some water, or something very small that my parents make me eat. I lost about 5 pounds in the last couple of days and i was always very skinny to begin with. i was never over weight i am just very tall. Im thirteen and i dont know if this is something normal that most people on this pill experience or if i should talk to my doctor or therapist when i go for a checkup. I read the side effects and weight loss is one of them. I can feel my stomach growling but i have no desire to eat. I feel like i just ate a meal. If i lost alot of weight just in a couple of days i cant imagine what it would be like by the end of august. Im still in middle school and i dont want the kids to think i am anorexic. Ive been taking vitamins though.Please help.

Symptoms: Weight loss, loss of apatite