You really should be giving every beer at least two weeks in the fermentor. Some beers, like wheats, benefit from shorter primary times, but most beers taste much better if you give the yeast time to clean up off flavors.
I have seen yeast ferment in as little as 36 hours, it depends on how good the yeast was. 24 hours seems a little fast, but I'm not going to say it's impossible. Just let it sit for a few weeks. Check your gravity in a few weeks and if it's where you want it, bottle.