Can't load into my world anymore that was working perfectly fine before

[WrittenSkate]

Yesterday when I loaded up my world with trains it opened perfectly fine, and a played a bit. Then I closed minecraft and went to bed. The next day, now I try to go back in the world, the world just gets stuck on "Loading terrain". It will also start "Not responding", and it will do that forever until I force close it, and minecraft launcher will give me error -805306369. Why is my world suddenly unloadable??? I did not change ANYTHING in the curseforge profile or anything.