What category is your cabin? Or better yet, give us the ship and the cabin number and we can tell you for sure.
Typcially its a bed (that can be split into two singles) and then a pull down upper bunk is in the ceiling. Although on the older CCL ships, there are cabins with bunk beds (upper and lower)... so we need more info to help.
Carnival Cruise Lines:
Fantasy 90, Celebration 95, Victory 05, Conquest 05, Spirit 6/06, Freedom 6/08, Holiday 7/08, Victory 6/09, Valor 9/09, Dream 6/10, Splendor 8/10,Conquest 8/11,Magic 11/11,Triumph 4/12,Spirit 7/12,Freedom 11/12, Triumph 2/13 - The fire cruise, Magic 1/14
NCL Dream October 2006, RCCL Mariner OTS June 2007, Celebrity Silhouette 2013