moved this to the Fire tips board where you might get a better response . . . Fires are really completely different animals than eInk Kindles.
Only thing I can suggest, given what you've said, is that there's a file management problem. They might very well be related. Have you tried a restart: hold the power button until it restarts -- don't just turn it off and on -- keep holding past that screen and let it re-boot itself. Sometimes that solves such problems.
It could also be a problem with your WiFi connection, so you might try resetting that.