When I run my game it changes the resolution (as expected) but when it does this it cuts off the top and bottom, plus the sides so i get some sort of weird view. Any help would be nice cheers :)

You have to enable display scaling in your video drivers settings or monitor.

Note the two options:

Stretch, will stretch your game to fill the whole screen(this can look ugly if its a 3:4 game on a widescreen monitor.

And preserve aspect ratio, which will stretch as large as it can without changing the shape of the game. Usually leaves some black bars on the left and right side of the screen.