My post url not showing in google?

A post on my website was indexed 3 days ago and was ranking in Google. But today that address has disappeared from Google.
I checked in the search console then it is showing URL in google. But my website is not there when I do site: my post URL. So what should I do?
Why did my post disappear from Google? please help anyone

This started from December 13, and until now it has gotten only worse, the reason could be that Google is overloaded or they're pushing something, indexing is slow, my new websites barely appears, Google Search Console is not even updating the specific info of posts (for example when you index them, then shows information under them),

I do hope things will get better from January since Google now is screwed up so badly and slow that is affecting all of us, it could be due to holidays as well, or any update.