That sucks. Sorry for your loss.

You should stop using Yahoo immediately. Billions of Yahoo accounts have been compromised in multiple hacks. I recommend a more secure email provider like Gmail.

Like others have said, the money is gone. At this point, you need to worry about securing your computer and accounts. I would follow TheWolf666's instructions regarding cleaning or formatting your PC. I would back up anything important and then format myself. Change your passwords, switch to a more secure email provider, and start using 2FA on your exchange accounts.