I was building a model which was just a single polygonal cube extruded a bunch, and I did a boolean->union to another polygonal object. The new mesh (polysurface1 & 2) appeared so I deleted the old meshes and went about editing the new polysurfaces. However upon saving the file, and reopening it, nothing appears. When I deleted the old meshes did I pretty much destroy my whole project? Is there any way to get that work back?

Any help would be much appreciated!!!!