So you are slim and short, how is your appetite , do you think you eat enough, How is your life going in Canada are you with your family, exercise is a good muscle building way to put on some lbs how about joining a Gym, going for work outs if not a Gym some power walking and climbing of steps ..Eat frequently small and nourishing food, drink plenty of water.We have some Canadian members may have ideas about their Doctors and Hospitals , check out our other forums and Groups we have a teen Social group here on MH .... Good Luck