Nomophobia
Nomophobia (NO MOBILE PHOBIA) refers to the dependence on the mobile phone and, thus, the fear and anxiety of time spent without it.
Typical symptoms of nomophobia include constantly checking your phone and the urge to respond to incoming communications and notifications immediately. A typical manifestation of nomophobia is nervousness when we do not have phones.
The need to constantly check the phone is also related to the FOMO (Fear Of Missing Out) syndrome, i.e., the fear of missing out on some important information or event.