To lose your head can mean to not have control of your emotions or to suddenly become very angry or upset.
But this is a government advertisement, uploaded by Cryptik, warning people to stay alert when using your card to get money or pay for something. See the rest of the woman in the background and the guy behind her trying to get a look at her code.
Actually, that woman could be me, going all big-eyed on seeing all that candy. ;-D
