Well unlikely you will not get points back
anyway the way rating works,
Why did I lose points/don't gain point with a win ?
Before each game, the server is adding more deviation to your score. It's not supposed to happen, but it's there to reflect the fact that you are not a robot, and add more dynamism to the ladder. What can happen in very balance games or very unbalanced ones, is this :
Your mean is slightly increased as it should be. But not a lot as the outcome of the game confirm your current rank.
Your deviation is lowered as it should be, but not that much as the game was not really meaningful for an adjustment. The result is your deviation being inferior to the number we add to it before it starts. (resulting in a increase of your deviation).
As your rating is Mean - 3 * deviation, and your mean doesn't move a lot while your deviation slightly increase, the result is a lower rating.
It doesn't mean that you lose points. Your mean will still be increased correctly. When this happen, it can be a 1 or 2 points decrease maximum. It's not meaningful.
its possible that you lose rating but 7 seems a bit much, but i guess its possibe, another thing could be that you left the game to fast (and your oponent maybe alt+f4 as well) before the score screen came up, in that case it will get count as a draw.