Invisible chunks

I logged off my world for a bit and when I came back lots of the chunks around the edges of my world were invisible or completely gone. It's an old world (not infinite) and have been working on it for a while. I cannot see any blocks that I break or place in the broken chunks. Part of the broken chunks I can walk into, while other pieces I physically cannot enter or break/place any blocks in, yet mobs are glitching inside the area. I’ve tried copying it, logging off my xbox live, putting on texture packs, but nothing works. I just want my world back : (