What happen if i lost my iphone 5? At&t?

I lost my phone i don't know what to do now. I mah call att after work.

You should call them immediately & have them deactivate the SIM in the phone so that if anyone should find it they wouldn't be making calls & you having to pay the bill. Also if you had Find My iPhone installed you could use that to find the phone, lock it, erase the data or if you think it is somewhere in your vicinity make a noise (even if it is on silent).