I've lost my model within the file

It looks like you hit the rather strange text bug. It seems that on some occasions when the geometry that a text label is attached to gets deleted, the text flies off to infinity. Nobody has yet been able to reproduce it consitently.
One way that sometimes works is to attempt to select the model, that you can’t see, by using a selection box in the middle of the screen. If you do get it you can copy and paste it into another blank model.