Is it just the crown (the bit of the tooth you can normally see) that has cracked/come off? How long was it cracked for?
If it's just been chipped it can wait until tomorrow, if it's a significant portion of the tooth (which then it would be bleeding quite a lot) then you may need to go to a hospital to get it put back in, but I doubt yours is that bad? (If a tooth comes out whole it needs to be put back in as soon as possible, which means a trip to the hospital or a dentist is better, but this is a dental emergency).