Where did Mail.app just put my email?
Create a Smart Mailbox with "Message is Unread" and sort it by Date Received. 
I have this setup as my default mailbox for processing my email. I also have the Mail.app dock icon badge set to point to this Mailbox so I can see how much unread mail I have, though in your case this won't be an advantage.

Pro Tip. Just mark all those messages as unread read. You're never going to read them.