iPhone storage full, can't delete photos or offload apps - please help!

Hi, does anyone know how I can free-up space on my phone in what seem to be unusual circumstances? I've only got a 32GB iPhone (7) and it's full. I've got 200GB storage capacity on the iCloud and have only used 49.9GB but I can't backup to the iCloud, apparently because my storage is too full. The same re backing up via iTunes on my computer - it won't sync because I don't have enough space on the iPhone.

The only app on my phone is WhatsApp and it won't offload - I select the option and nothing happens. It also won't let me delete photos - I select delete, go to my deleted photos folder, and they're not there but have reappeared in the 'recent' folder when I check back. There also seems to be a backlog of photos 'somewhere' - occasionally, when I turn my phone on and go to 'photos,' it says 'updating paused for 7,033 items.' I don't have any other apps and have deleted my history and data from Safari, but still have a huge amount of storage capacity taken up with 'other.' I'm desperate not to lose my photos. Does anyone have any suggestions for how I can get my phone working again? Thanks.