Gallery isn't saving my pictures or videos
This isn't the perfect answer I couldn't comment so that's why writing it in answer. First of all tell that do you have SD Card in your phone, if so then first try removing your SD Card and check again. If that fixes your issue then install back our SD Card to phone and then navigate to File explorer, from there Goto SD Card then click on settings and then un-hide the hidden files and delete them. This happened to me once and the trick worked. Hope it helps you also