I am looking for a vlookup that will look up different tabs based on dates.
I have been looking through the INDIRECT questions but I cannot get my
formula to work.

I have a report that I run everyday and save this report as different tabs
with the appropriate date as the tab name. I need the net change from
day-to-day. I need to lookup the previous days data (saved as a tab with
that date) and then subtract it from the current days data.

Here are 2 different versions I am working on:
=IF(ISNUMBER(B7),"",VLOOKUP(B6&" Total",INDIRECT(""&A6&"'!A:B'"),4,FALSE))

=IF(ISNUMBER(B7),"",VLOOKUP(B6&"
Total","'"&INDIRECT(TEXT(A6,"m-dd"))&"'!B:E",4,FALSE))

These formuals are on my current days tab which is Apr-20. Cell A6 shows
the current date of Apr-20. I would like this formula to vlookup the
infromation from Apr-19.
Thanks!