Just another note, I would avoid the use of tinfoil as it can reflect to much light and create hot spots that can burn the plant like a magnifier glass.
You don't have to worry you can put them back on the 18/6 cycle. Its always good to check in on them daily if possible. Maybe Santa will bring you a new timer.
No they are to young for it to have any major impact. Its better that it was lights on with no sleep then lights off. Set your timer and enjoy.
Happy Growing.