iPhone being a little strange?

When I have been on Safari on my iPhone 5 tonight, the black bar at the top of the screen (with time, battery percentage, signal strength, etc.) will just vanish, and then come back for a few seconds every once in a while. There will be times that the blue bar that tells you what website you are on will vanish as well, although if it stays put and I scroll down the internet page that I am on, I can see another part of the page above the internet bar in the place where the black bar at the top should be.

Also, if I attempt to type something while on Safari, the keyboard simply does not come up from the bottom of the screen. Has anyone had this problem before, and what did you do? This has happened to me a couple times before.

This is an unrelated issue, because it has been going on for 6 months, but my iPhone speaker will sometimes not work. No, the speaker isn't broken, because when the phone decides to play sound the audio works fine. But the volume bar at the bottom of the iPod screen will vanish, and you can't hear any sound. For some strange reason though, it decided to start working a few weeks ago and I have been able to play sound. But even now it has gone on and off a couple of times...can anyone help me? The Apple Store told me that my phone was water damaged (even though it literally was only a few drops that got on it), and they could not replace it for free because their insurance policy does not cover water damage (am I the only one that thinks that's crazy?)...ugh. Anyway, my question is why did it decide to suddenly start working again?