How can you loose an entire bed? <img src="/ubbthreads/images/graemlins/silly.gif" alt="" />
Anyway, you can get it another bed (see below), or just combine two piles of straw into a hay bed (click on the straw to bundle or unbundle it). If you combine them on the ground the hay can not be moved, but you can combine them in your inventory, or a container, and carry it around.
Lost Items - guide and directory of inventory files