email lost from trash

So last night I was deleting all emails from a specific sender. Apparently, the xfinity email app has changed in that instead of moving all the emails I had in the Search to Trash, it moved everything from my entire Inbox to Trash. I had thousands of emails from the past 5 years. I went straight to Trash to move them back to Inbox, but there were only emails from the last 4 months. I download emails to Thunderbird but they are missing from that app also. When I open Thunderbird, I get the message "your deleted emails can be purged from the disk". Does that mean I can still retrieve those emails?