Excel reader - column names with dates in them

What I am trying to do is create a flow that will automatically add a new column to the end every day with a new total. Essentially, I want to know the counts of certain things every day so we can track variability.

So far this is pretty easy, I’m reading in the previous day’s data, using a groupby command to get the totals and then joining the previous day’s file with the new numbers. I even have the date going into the column name pretty easily.

The issue I am coming across, however, is excel reader is refusing to bring in the previous days worth of columns because they have a date in the column title.

What can I do to make sure those columns are being brought in? I can’t lose previous day’s worth of data.