overworld builds disapeared? HELP!

[budderswift11]

I had made a giant mantion and now its just gone so basicly me and my cusin were on my superflat world he was in the overworld and I was in space (space station) he died by jumping off  a tinker construct building in a village and when he respawned its just gone the strange part is that it was only the over world stuff that had disapeard my space stations stuff and my other diamentions stuff was still their. I spent 3-5 hours on it and now its gone. I NEED HELP! this was my 1 chance at getting my builds on my favorite utubers channal and you would want help if it hapend to you so can someone help me out.(p.s.  I mean chimneyswift11). someone respond plz

Edited February 21, 2014 by budderswift11

[budderswift11]

also I had used the following mods in the build and when it disapeared

chisel (build and station)

t construct ( the building he jumped off)

galactic craft (I was in space)

crayfish furnature (build)

flan(call of duty fun)

(think that's it not shure)

Edited February 21, 2014 by budderswift11