Camera Roll photos missing - iPhone trying to restore?

Was looking though old photos on my iPhone Camera Roll this afternoon - I have approx 16,000.

So I was flicking through them quickly and then it froze and crashed. Sometimes the Camera Roll does this but once I click on it, it restarts no problems every time.

But not this time!

When I reopened Photos it shows "Camera Roll"+ "Recently Deleted" Photos at 0, as in all gone! I thought they'd all been deleted but it doesn't seem they are.

My memory was almost full before and it still shows the same amount of memory left.So it doesn't appear anything has been dumped.

When I open up Photos and leave it open, the Photos start to restore and the rest of the Photos start to come back into "Camera Roll", "My Photo Stream", "Favourites", "Panorama", "Bursts" and "Recently Deleted". At the end of the screen it says "Restoring".

So it gets to the same number every time 15,772 Photos and it freezes again and crashes. When I go into Photos again it shows "Camera Roll"+ "Recently Deleted" Photos at 0, as in all gone, or at least not showing.

I have retried this all day and don't know what else I can do. It's like the photos are there in the background but can't be accessed. When the iPhone shows "Restoring" they come back but then freeze again. I'm going around in circles and worried that I might lose all the photos.

Can anyone help please? Anyone see this before?