Hard Drive - how to undo Accidentally overwriting external hard drive

So my old iMac died and i ended up getting the hard drive put into an external enclosure and getting a Mac book pro 2018 with high sierraI attempted to restore the data from this hard drive to the Mac book pro using the directions I found on this websiteRestart your Mac.While the startup disc is waking up, hold down the Command and R keys simultaneously. You're Mac will boot into macOS Utilities. If it doesn't, try again.

Click on Disk Utility.Click Continue.Select your Mac's hard drive.Click the Restore tab at the top of the Disk Utility window.Select the external hard drive that your cloned backup is stored next to "Restore From."Select your Mac's hard drive next to "Restore to."

I clearly didn’t follow the instructions carefully enough. Because I ended up over writing my old hard drive with the data from my empty new Mac book. Is there any way to undo this?