If you got no time to read Google's notes, you may have been suffering of a death scare when seeing a significant drop in the average ranking of your results in the Google Search Console.
It is never too late to find out that the "free fall" graphic is a mirage, like an SEO reprint for the Myth of the Cave...
An incremental improvement in Google's logging system now provides better accounting for results in lower positions.
This change might cause increase in impressions, but also a decrease in average positions.
This change only affects Search Console reporting, not your actual performance on Google Search.