People calm down Kakashi is not going to die and he is not going to lose his Shiringan, and here are reasons why.
1. Kakashi is a main character and will be alive to see the end. He's to big of a character to just kill off plus the fact Kishi just kilt off a major charactor not so long ago, so it would be stupid for him to just keep kill off his major charactor.
2. Kakashi has MS. It wouldve been stupid for Kishi to give Kakashi MS and only let him use it once in the whole manga. Kakashi's MS power is to warp things so he probably warped the nail too or someone step infront to take the hit. I know some of you going to say his head went back. His head going back is just a natural reaction that come from something getting thrown at your head. If you've ever had something thrown at your head youll know what im talking about.
3. In Kishi interview he said that this year is suppose to be about Sasuke and it has been mostly about Sasuke. Next year is suppose to be about Kakashi and Sakura. Well guess what its not next year. Why would he say that if he was going to kill Kakashi before it was his year. Also in that interview he says "Sakura needs to grow up" i dont think that Kakashi dying will make her grow up. The thing that will make here grow up is the death of Tsunde. It would make her sad that Kakashi died, but lets face it Kakashi really didnt train her, he might have taught her something but Tsunde taught her most of everything she knows. Also in that interview he said "Something big is going to happen to Kakashi" lets not forget its for next year. I guessing that he will he Hokage is what im guessing. Their is nothing really big enough that i can see, but Madara being Tobi and Kakashi see's his face and relize it. With the big thing being Hokage i think Tsunde will die which will make Sakura grow up.
Their is just some reasons why he wont die or lose his Shiringan.