My Contacts just disappear. I did nothing abnormal

My phone is iPhone 14 promax. I have just updated my phone to iOS 26.1 yesterday. Tonight I updated watchOS on my watch. Shortly after that, I check my phone and found out I lost nearly all my contacts (about 1-2000 phone numbers from 2019-now). Now my contacts only remain 12 phone number I saved recently (about 2 weeks ago). The last time I check the contacts being normal was 2 hours ago. In that time I did nothing abnormal, just social app.

I could lose my job because of this! What should I have to do?