Sry you have lost all your POP emails.
If you are getting disconnecting email then its not normally anything to do with eM Client and more of either a eg: physical internet connection issue (not stable) or some other program running interfering causing the disconnection. Would need to be troubleshooted via the error log in eM Client once you have the account restored again.
As you have now removed your POP account, the only way to restore the account apart from reimporting your Outlook account again is (if you have prev made a manual backup in eM Client) via “Menu / Backup” you can restore the backup via “Menu / File / Restore” or (have created a complete image of your computer) and can then manually restore the eM Client database.
You can setup automatic periodic eM Client Backups which create .zip backup files to restore if needed.
Click “Menu / Settings / General / Backup”.
(How to setup automatic periodic backups in eM Client) example
If you have imported your POP email into an IMAP account and the email are all synced to your IMAP server, then just reset up your account in eM Client as an IMAP account and no import required.