Help please

So I'm 16 gunna be 17 in 2 months, I'm 4'11 and I weigh 88 lbs. I've began working out and everyone says I'm crazy because I'm already small. I get I need to gain weight which I will but I don't want to gain it from eating unhealthy all the time and getting like unhealthy weight. I'm trying to gain weight in muscle growth. I'm currently taking Mass Gainer Complex Protein twice a day, before and after I workout. Which is 700 calories in all. During the day I eat healthy, smoothies with a little protein in it. Just fruits , vegetables, my refrigerator is stocked with healthy foods. But I need help with supplements and the kinds of workout that'll help me and how to prevent myself from passing out from dehydration. I drink a whole bottle of Gatorade before workout and then I drink a little water after every set and I still end up getting dehydrated.. Amy tips on how to prevent that ? And what supplements I can take to help me get muscle and tone?
Source: Cystic Fibrosis Exercise and Fitness Forum - Category: Respiratory Medicine Authors: Tags: Exercise & Fitness Source Type: forums