I suspect that when you moved your model, your model and your level markers became seperated. (Next time, move the autocad file to your model, not the other way around) Your plans will still exist, becuse the level planes exist to infinity, unfortunately, the level markers do not. You might try going into an elevation and un-crop the view then zoom way out. With some luck, you might see the levels way far away, and you can just stretch them back to your model. You'll have to do it in perpendicular views so you get both the x and y directions. Most likely you'll have to zoom out pan over, and zoom back in and repeat a bunch of times to locate it.