I had a problem with my phone since last night my Safari, phone ect links at the bottom have vanished. It's just showing an empty gray space anybody else had this before? I reset settings and had no luck.
You may have an app that conflicts with either another app or possibly the OS itself. Not all apps are compatible or play nice-nice with other apps. It's too weird that not only did the icons disappear, but they showed up on another page and you had to physically move them. You might try uninstalling apps one at a time going back to the time when this problem surfaced, especially if this problem continues.
Before you go to too much trouble, check to see if you accidentally created a folder. Your missing icons may be huddled together, hiding from you in a folder you didn't mean to create. I learned this the hard way when some of my icons disappeared.