Which rating system??
Does the rating system actually work?
I see you're new.
New players (and inactive players) get a multiplier put on their rating change. So you may gain (or lose) 100s of points in the first few games. Not quite as many the next 5 or so, and so on, until you're considered an active player. Then your rating change is normal (usually 5 to 15 points per game).
This is the Glicko rating system in a nutshell.
It's all in the title.