My iphone decided to deleted all my apps?

My phone died before it said 10% and I charged it. It turned on a few minutes later and I decided to go on my computer and checked on my phone. All my apps are gone. I have 6 main (I guess that's what you call them?) apps that are calendar, camera Game Center, App Store, settings and newsstands. How do I fix my phone and get all my apps back and my phone returned to normal? Please answer!

How to delete all the music off my iPhone?

I synced my iPhone to iTunes on my computer. I've got a lot of songs in my iTunes library and my iPod has them all on it. When I synced my phone it randomly downloaded like 72 songs onto it, and I want to delete them all and start fresh. How do I do I delete them all (without altering my iTunes library)?

(Sorry I'm terrible with technology)

Are there iPhone glass screen protectors which are completely free replaceable lifetime warranty?

Are there iPhone glass screen protectors which are completely free replaceable lifetime warranty?

Added (1). When I bought my iPhone 6, the people at the AT&T store told me that if I got the $30 glass protector, if I ever dropped the phone and the protector broke then it would be replaced for free… I got the Bodyguardz protector, and apparently replacements cost $14. Are there other brands that are completely free replaceable, and I just took the wrong thing?

Can't restore iPhone without signing into iCloud?

I have an iPhone 5c that runs iOS 8.3, and I've been trying to reset my phone. When I went to, it told me to turn off find my iPhone, so I tried, but it said I needed to sign into iCloud in order to do any of this. I don't remember my iCloud account. At all. Is there ANY way I can reset it without this stupid iCloud stuff?