Crashing

So over the last week my game has been crashing very often. Lag is a major issue too but the crashes come seemingly at random. Sometimes after and hour sometimes a couple minutes. Just a few minutes ago my game crashed as I died, when I came back I was at spawn and my dropped belongings were gone. Items don't despawn for 5 minutes and I was only away for 1 or 2. Lost a lot of good stuff. 

Side question: is there a way to bring up a backup on a seed that's not a realm?