Why do I always win 15 points and always lose 25 or more

Dear all,
I'm not a whiner (or I think that i'm not :p) but why is it that I every time lose far more points then I gain when I win. This just doesn't add up. Am I doing something wrong? Is it normal to lose more than you gain. If so, what happens to points I lose to other players....
Does anyone have an opinion on this?
Thanks
I'm not a whiner (or I think that i'm not :p) but why is it that I every time lose far more points then I gain when I win. This just doesn't add up. Am I doing something wrong? Is it normal to lose more than you gain. If so, what happens to points I lose to other players....
Does anyone have an opinion on this?
Thanks