Steam games resolution is terrible

Hello!

I'm trying to play steam games on bootcamp but the only problem is the resolution settings is so bad. In team fortress 2 for example it shows a squared screen with bars on left and right. My cursor is gigantic everything looks really bad. I also can't click on anything directly on it I have to find the buttons some were else like there invisible and there not were there supposed to be. Can someone help? Thanks!

I'm using a Macbook Pro 13inch with Retina display newest model as of 12/1/15