That's not the only thing not working. Your Prev YTD Clicks are not correct either.
Sorry, I should have explained a little better. The code is meant to show clicks or impressions as long as it is within the Month/Day of the reference date. Each YTD cell should match its adjacent cell, up until the same time as the reference date, regardless of year.
I changed the name of the column header to avoid further confusion I probably caused