My contacts disappeared?

All my contacts mysteriously disappeared when I was holding my iPhone (4) a couple of weeks ago. All my contact's names still appear on my messages and recent calls, etc., it's just that my contact list has gone mysteriously empty. I have already clicked on 'groups' and selected 'show all contacts' and this doesn't seem to make a difference. Everything else seems to be working fine - it's just the contacts that are missing!

I didn't have my contacts updated on iCloud so I am not being able to retrieve them.

Has anyone experienced similar problems? Or does anyone have any idea how to solve this?

If so, please reply below! Much appreciated 🙂 x