World wont load chunks

[Axeboy395]

Well my favorite modpack, it used to load just fine, life was good. About two days ago, my world loaded as a small, chunk of land floating in nothingness, rays minimap also showed just a square,if i go into the nothingness i fall and just float, nothing loads or happens, i tried to change the settings and nothing helped. i have deleted and installed, worlds, the modpack, and the technic launcher, i have allocated 6 gigs to technic pack, and my other packs are really laggy.