Iphone 5s Stuck with apple Logo and loading bar

My Iphone 5s is stuck with the apple logo and the loading bar and has only got about 1/20th of the way across. I have done the rebooting thing and it just returns to this, i have also tried plugging into my mac but i can't trust the computer because i cant get past the logo and loading bar!

I am going on holiday soon and need it to work, please help!

Thanks