Brickmaster:
First, you are in that age when it is very hard to gain any weight, not to mention muscles, your testosterone level is high, but also your metabolism speed is very high...
You can do few things:
Eating more than 3 times per day, optimal is 5-6 times per day, that will also keep your metabolism speedy, but you need constant nutritions.
Exercise, i take that you know how to, based on your post,
Carbs/Protein are your best friends, approx in 70/30 ratio
Drugs wont help you, because you don't need more appetite, but a way to keep that food, but your metabolism is so fast that food simply runs through you...
Did you take protein powders (supplements) or just food based proteins?
What is your height and weight?
When I get home, I can write my experience with the same problem in the age of 19. It may help you.