delete previous months data

OK essentially this is my problem:
I have a daily spreadsheet, uou update for inputs and outputs each day and the spreadsheet gets to an overperformance figure (sorry if the spreadsheet is a lottle unclear, it is a simplified version)

On the first day of each month, the opening target is adjusted and you start again. The probelm is you dont know what the opening target is until roughly 21st of the month.

I created a macro that deletes the opening target and removes all the previous days before the start of the month.
The way i done this was:
Create a copy of "daily" tab, change b5 to equals c2 and copy and paste special as values. Then in d5-d58 and f5 - f58, vlookup values from old "daily" tab , and then copy and paste special as values. Then delete old "daily" tab and remname daily(2) as "daily"

What i have done is essentially created a new tab on 21st March, looking back to data only as far back as 1st Mar and the new opening bal and target is found. The macro can be used on the 21st of each month.

but...macro doesnt work, i have tried a few times and i think it is because i am vlookuping up data from a tab that i later delete...please help!! - thanks a mil to anybody that can give me a steer in the right direction.

Sorry if i am unclear, please feel free to ask for clarification