What I also find strange is that on iCloud it only allows me to see/choose from two backups, one from the day of the lost contacts, and the other from the day before. When I tried to restore from the day before, nothing changed, still the same contacts. Is it normal that older backups than that...

Thanks for confirming that. However, that leaves me even more baffled because then I have no idea what caused my recent contacts to disappear over night. And what I should do about it.

Not at all, only that message saying my iCloud is running out of storage. But that's been there for a while. Could it be due to some iOS update during the night or something..?

Thanks for your reply. Thing is, I don't have a Gmail and I've never owned an Android. I've only used the iPhone and iCloud. I have not either done any mass deletions ‍

My more recent contacts suddenly disappeared from my iPhone 6 Plus iOS 12. When I login to iCloud, the more recent contacts are gone as well. The contacts that remain are really old since way back. I have tried almost all of the obvious solutions posted online. Toggling on and off contacts...