The SEO community seems pretty upset that if you go into your Google Search Analytics report within the Google Search Console, you will be missing a day, specifically March 9, 2017. Here is a sample chart showing the gap in the day completely gone:
Truth is, this has happened before back about a year ago. It was a bug that fixed itself then and it is a bug that will fix itself again in the future.
@Andrew_Isidoro Me too :). Should be resolved in the near future.— John ☆.o(≧▽≦)o.☆ (@JohnMu) March 13, 2017
But the amount of concerns posted on social media and Google Webmaster Help are pretty high.
So, again, do not worry, I know the timing is weird with the Google Fred update but I doubt they are related.
Update March 14th: This bug has been resolved.