I screwed up my part and I don't know what I did. Can someone tell me what I might have done?

I have a part that seems to have, well, for lack of a better way to put it, seems to have gone all thin walled on me!

The part was a 3-inch long pipe segment => 2-inch OD with 1/2-inch wall thickness. I used extrude cut to drill a 0.025" hole through the pipe wall perpendicular to the axis of the pipe segment. Then I copied a circular array of the little holes - 25 of them equally spaced around the outer surface of the pipe, all pointing directly to the centerline axis of the pipe. The part was perfect. Then I did something quite by accident that seemed to remove the material of the pipe, leaving only a shell.

Looking at the outside of the part, all seems normal. You see the outer cylindrical surface. You see little circles on that surface where the holes were drilled. You see flat planar outer surfaces on the square cut ends of the pipe segment. You don't really see anything on the outside that reveals the part is screwed up.

But looking on the inside, you see the inner surface of the OD of the pipe segment. The ID surface has disappeared and all the material is gone. You see the array of tiny holes drilled - they look like little tubes 1/2-inch long. You should see just the circular edges left when the drill bit penetrated the inner wall of the pipe segment. It looks like the entire part was made of paper with near zero thickness - a mere shell of what the part was. It's as if you dipped the part in ink to cover ALL surfaces, then wiped the ink away from the pipe's ID cylindrical surface and then magically made the pipe material disappear, leaving only the very thin shell of the OD, the tiny drilled holes and the planar end surfaces - just the ink and no pipe material.

So, I'm sure I've done a pretty poor job of using words alone to describe a 3D ailment. I feel as though everything inside my body evaporated, leaving only a monomolecular-thin rigid shell of skin as an indicator of where the rest of me used to reside. With no idea what to do, I turned to you folks for help.

Ideas? Anyone?

OK, as you've probably guessed, there's more to the part. It's not just a simple pipe segment. If it was no more complex than drawing a pipe segment of fixed length with an OD cylindrical surface and an ID cylindrical surface with a circular array of pin-holes, I'd reboot my box, launch Solidworks 'n do all the work again from scratch, throwing away the corrupted file. Can't bring myself to do that just yet. So here's what I've done.

I saved the corrupted part file under another name. I opened the newly created part file and deleted EVERYTHING from the feature tree in reverse order of creation - all the way back to a single closed sketch in the Front Plane with a construction line about which to rotate the sketch. I then did a Revolved Boss/Base feature to recreate my fundamental part. It now seems solid. There is none of the hollow frame-like thin-skinned crap that just appeared out of the blue one day. I honestly do not want to have to recreate all of the additional sketches, features 'n other objects again. Can I import objects from the feature tree of Part_A.SLDPRT into Part_B.SLDPRT? Is that even an option? Am I looking at a total loss of all my work in the first file and having to recreate every single part of it again? Am very slow at it all.