photos have deleted from my phone??!!! pls need urgent help

So, I will start from the beginning.

So in the beginning I had 5200 photos and everything was fine except that I couldn't take any photos on Snapchat. So I decided to delete some pictures. Except sometimes the deleted pictures would just come back in like 2 seconds. And sometimes it would say 5 photos selected but I couldn't see anything selected?? Or I would have to touch SELECT over and over.

Anyways fast forward a few hours and I got on my phone, except now it says I only have 3600 photos!!! I lost some pictures, mostly the ones earlier in my phone and then some of the pictures I deleted months ago and like last year came back. And I have pictures on my Recently Deleted, except not the ones I lost!!!

i feel like my phone has somehow gone back in time or something.

And I lost some pictures from a wedding and I totally regret keeping so many 😟((( pls is there anyway??

also i need some help using http://www.ipad-converters.org/recover-photos-from-iphone/ this like also.