My Iphone 5 just says "searching"... how do i fix this?

Since this morning, on top left corner where it would have the carrier name along with 3G,4G (etc.) it just says "searching..."

Usually i have LTE all round this area. i dont know whats worng. I've tried to restart and shut down my phone many times nothing works! also i reset the network settings,, still nothing worked!

i cant make any calls or text. Please Help!!