Minecraft: Can you undo something in minecraft?!?

I have just come from minecraft after an outrageous event, so I type this very angerly! I just spent over 2 hours building an amazing wooden mansion in an amazing world! I have been playing minecraft for less than a year now and have a realy cool building mod (too many items). So there i was in my GIANTLY HUGE LONG AMAZING mansion, im placing brick all around a block of netherack to make a fireplace, (the last thing on my agenda!) and the fire jumps like 20 feet to wood and lights the whole place alight. Im placing water all over the place like a madman but it doesnt work. I give up and go to my watch tower up on a hill near there and see it all just burn. Now theres just some fences, stairs, and a few patches of wood. Also theres an OCEAN where it used to be. So i was wondering if there was a way to delete files or get a mod to rewind my world. PLEASE HELP! I know this has happened to almost all minecraft players but it was HUGE AND AWESOME!!!!!!!!