When I put on shaders then it was laggy so I tried to make the windowheight and width smaller but then I cant put it back to normal because its to small

Oh, I see your predicament because I just did this to myself, so you would be given an answer.
Go to the Toribash folder by right-clicking the link to the game, and select open file location.
Go to the Toribash file default.txt and make it text, if not already. It's not in any folders. Open it.
Scroll down the text file until you find, width "XXX" height "XXX", and change it to width "960" height "540". Default size.
Done!

Thank you very much :3