Saw this info and am passing it on:
IF YOUR FRIENDS SUDDENLY DISAPPEAR...
think if you go to your own page and hit the edit button in your friends box (right upper side of the box) you can enter in the range or number of friends want to show in your box. It happened to me a few months back.
Debi 2 days ago
Have you clicked the "Edit" button at the top right of your block of Friends pictures? It has a setting for how many it will show.