Lost all my iCloud contacts?

I updated my phone to iOS 13 last week and restored the backup of my previous system, but although everything else was restored, I was left with an old and outdated version of my contacts, assumedly from iCloud. When I went through and deleted all the people with whom I no longer have contact, I was left with only a handful of contacts I'd made in the past few months. I don't even have my parents phone numbers. Is it possible all of my contacts could have been somehow deleted from iCloud?