Crashing every time I open a specific world

I've noticed a bit of lag on my creative world because I am currently creating a map that involves a lot of entities and command blocks. I started lagging so much to the point that my game crashed, so I just opened the game back up again, and clicked on my creative world, but when I tried to join, it just crashed again. My internet is working, and I didn't have any entities around me to cause this. If it were corrupted data, then I would have received a screen that says "this world has corrupted data in it" or so... I tried joining again multiple times, and the same issue kept happening. I created a copy of the world and joined it, the same result. How can I fix this? I've been working on the map for a very long time and I really don't want to delete it.