Unreal engine random crash, now wont load my project

Hi,

I’ve spent around 20 hrs creating a project. i am gutted now because i had (my first) a Unreal engine crash!

I thought it was a little strange so i tried to open it again. But, it gets to around 99% then fails and crashes!

The last thing i noticed was, ive added a small lake recently and for some reason it only appeared looking from one direction?!(but it was fine for a while after first placing it)

So i located the “water” in my scene but it wouldn’t let me click it to delete.
Shortly after this it crashed and i cant find anyway to recover anything.

Please help!
Mike