I didn't think this would happen so I didn't create any backups yet.
So me and my friend were messing around in a creative world. We were using repeating command blocks with snowballs by making them spawn random entities. My friend added a repeating command block that spawned cod on bobbers. He thought it would be like the thing on the end of the fishing rod. The server started lagging a lot and then it shut down. Found out yesterday that bobbers were actually when the fish jumps out of the water. We thought if we just disabled command blocks it would work but the server wouldn't start up and kept crashing probably because there were already too many entities. So I tried restarting the server again with animals off but then it just sent me to a fresh world and moved the original one aside. I don't know how to access my original world please help.