I Was trying to log on to a singleplayer world (one of mine) and it instantly crashed

Put the summary of the bug you're having here

*What I expected to happen was to play one of my singleplayer worlds

*What actually happened was it instantly crashed

Steps to Reproduce:
1. Log on to minecraft and (mine was offline for some wierd reason that i cant fix)
2. Click Singleplayer
3. Select a World (mine was labeled Big Project)