Yes it's becoming normal to feel anxious and insecure simply because a lump of technology has been left behind or forgotten. Yet we don't really need a mobile to function - it started out as a luxury but now it has turned into a necessity.
For people over the age of say 45 it's relatively easy to consciously say - I'll leave the mobile in the house for the two hours I'm out walking - but younger people find it much harder and can get very stressed out if they misplace, forget or lose their mobile. They seem to cope, but the world is a far more tense place in which to live.
So detachment is normal and the vacuum is filled with anxiety!