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.
I think I figured it out. I inserted a sketch picture and did not use the scaling line to scale the picture. It was floating out in space to the left of the model. Would be nice if it could be deleted but I just made it smaller and moved it to the origin. Problem solved.
If you double center mouse click on a feature while rotating, you'll rotate about the feature. Rotate around a vertex, hinge on an edge, etc.
That means one of your lines or a point is far away from the part origin, check your sketches...