My base on my private world keeps on dissapearing

I made a world, had it private, and made a base. Then I went mining for coal for torches to keep mobs away. I cam back, and my oak plank base was GONE. Evrything in it was gone, the crafting table, chest, and garden. I made a better base on top of that same tree, and I went food-hunting. I come back, and my base is GONEEEEE (I used /home to get back to my base) Please help, or fix this bug asap! Thx!