marijuana plants will suffer much more when over-watered rather than under-watered. Alot of growers actualy tend to under-water their plants during vegetation because it enables the roots to stretch down further looking for water. If you do think you have over-watered them, i would leave it 3 days MINIMUM, or at least until the soil is SIGNIFICANTLY dryier (you can tell either by stickin your finger in....but a good way is always to go by the weight of the pot.....lighter pot means less water)
You shouldnt be affraid to let them go without water for a little bit, if anything it does them good!