FIrefox removes all of your data when you Reset your password. You can also check out this link: https://support.mozilla.org/en-US/questions/1295116

checking it out

so there's no way to recover it back ?

Most of the users don't generate a recovery key due to which their passwords can't be recovered. If you have generated one, you can recover it through this link: https://support.mozilla.org/en-US/kb/reset-your-firefox-account-password-recovery-keys If you didn't generate a recovery key earlier, you might've recovered it as it saves the profile on the same Desktop. But as you switched to a new one, it may not be possible as it requires files from your old pc. If you can get those, you can recover them and here's the guide to it: https://support.mozilla.org/en-US/kb/recovering-important-data-from-an-old-profile#w_passwords