Online beginner

[Brewster]

Hi, I'm fairly new to poker (6 months) and I've played about 700 games or so on-line. I've lost about $400. I usually play $5 no-limit 9-person tournaments, and sometimes the $10, at FullTilt. Is this a good place for me to be playing and should I be disheartened that I'm down so much so soon? I feel like I'm a competent player, I just get impatient sometimes, or go on tilt and blow everything I worked all week to earn. Anybody have any advice?

I've read the Harrington books, and I've got the Sklansky's No-Limit Theory and Practice book.

UPDATE: I just found a post with the exact same question, but I'm a little confused. Are Sit-and-Gos always the tourneys or are cash games called SnG as well?