Don't panic! What do the tickets say on them? There should be a small strip of printed text on the back telling you the final date they can be used and the number of days of the ticket. They do have different ones depending on whether they're 1 day or hoppers, or whether they're adult or child. One variation is green with mickey ears, with the castle in one ear and the earful tower in the other.
Unless they've recently changed them... (they are ready for an update, I think)