Strange behavior of the site after December Core Update (Impressions stayed the same - Clicks dropped)

Right after Google rolled out December Update, my analytics started acting strange - what is happening is that my clicks (traffic) fell for nearly 50% but impressions and overall ranking stayed the same (as I can see on Ahrefs as well). Ranking actually is improving steadily (as it was before the google hit). That just doesn't make sense to me. Ill post the picture of the stats showing this in comments. If I didn't lose any ranking and impressions, how come I lost half of my traffic? Can somebody please explain this phenomenon? *The website is a 1 year old blog about art of cinema and had pretty good analytics / stats before the update hit.*