I recently started a new model. So far I've added one plane and some sketches. When I click the isometric view zoom button the model is very small. It is not zooming in enough. It is almost as if Solidworks thinks there is some other larger features or geometry off to the left. When I try to rotate the model with the mouse it easily rotates off the screen because it is not pivoting about the origin.
That means one of your lines or a point is far away from the part origin, check your sketches...