You have the option to undo an accidental deletion. Simply press Undo at the bottom of the screen to revert. You can adjust the Undo options under Settings – List – Enable Undo function (it activates the Undo action) or Time to Undo (it sets the number of seconds the Undo button remains on screen after you have deleted something).
If you failed to tap Undo, you can still retrieve your deleted items from My items (three dots menu top right of the screen – My items tab).
Check here for more details.