Excel Pivot Table

Hi

Could someone please help regarding the following matter:

I have a table of data (with data added daily) and I want to create a pivot table that essentially states volume figures per subcategory of data per month for next 3 yrs or so. Each horizontal line within the tab is an 'entry,' but the entry may require its volume (which may differ each month) to be split among multiple months and potentially, multiple categories.

It might be easier to send you a spread sheet to understand the issue.

Any help would be much appreciated, as I am struggling firstly how to set it out, to which then apply a pivot table to.

Kind regards

Adrian