Import data from changing sheets

I have a spreadsheet that is used for reconciling daily business sales. Data is entered on the sheet then a macro makes a new sheet for the next day. So, there's 365 (or 6) pages in the year's file.

I want to generate a month end report for each specific month. So, I will need to import data from different sheets each month and I'm at a bit of a loss on where to start. The daily sheets are named as a day of week, day of month, month, and year.

I'm not too concerned about whether the process is added to the current sheets or is in a new workbook. And, my next step in the process will be comparing to last year's data.

Thoughts?