Could you please send me the file to have a look at it. To do so go to www.wikisend.com and upload it. You will then get a page that has the download link. Copy the download link and come back here and paste it in your reply.
If the file has sensitive information let me know before you upload it.
Ok I think you are referring to "Filters" and not Drop Down controls. If so, Filters in Excel can only be applied in the columns. However I may be able to find a workaround if you can show me a sample output sheet showing how you would like to see the data when 'filtered' on Months for example.