most plants that are mature or clones do not need 12 hours of darkness to start flowering which is why your plants started to flower, you could of added a light inside the green house on a timer to extend the day just a couple more hours and they would still be in a veg state but 10 -11 hours of dark period is long enough to trigger flowering for most strains.
they will probably reveg but it will take a while and you will have some weird growth with some 1 and 3 bladed fan leaves.