Just loaded my save file and i was in a desert not in my mine were i left last night. Ive lost 8 months work

Ive lost 8 months work in my mine.when i loaded my save i was in a desert not my mine,when i got too my mine it has changed ive lost my furnace area and all my chests an also the stairs too my houses so i cant get back to them but i probably lost them too.this is the second time this has happend.my strip mine was that big it takes about 5 minutes to fly from one end to another thousands of hours work can i get it back?