My iPhone keeps resetting with the apple sigh and glitching, help!

Okay so my IPhone has been acting weird, but this sucks. It keeps resetting to the apple logo sign for a few seconds, then the apple has lines through it and sometimes a blue line appears across the screen. Then it disappears slowly into a black screen and starts the whole cycle again! Also it shows a I Tunes sign and has a charger under it, this screen pop ups randomly and it goes away or stays till I press a button. I have read some things about it like how you need to back it up on I Tunes or something, but what if I don't have it and they also saying you need a computer. I may not have much to explain sorry about that but I wish for answers, thank you!