Seeing Concerning Indicators Around Search and Organic Rank

I am using Search Query analysis, and found that not only are some of my former best sellers being affected by lower keyword impressions where the search terms still convert above market levels, but my organic ranking is half what it was last year with no change in my ad spend or strategy. I regularly update my listings to put trending keywords in bullets and titles, and test them and images through A/B experiments. Are others seeing similar results? Could the algorithm have changed, and if so, does anyone have recommendations on what can be done?