Tamara,
Last year we upgraded our PDF delivery module. The upgrade provides a more robust and flexible method for delivering PDFs, but one of the things we lost was that single consolidated list of all PDFs you had ever purchased that used to appear on your order history page. (It’s been gone for almost a year now, and this is the first question about it we’ve had. I guess that confirms that it wasn’t something that too many people were using….)
You can still see your past PDF purchases by opening each of the orders listed on your order history page, but there’s no longer the ability to see all PDFs purchased together in one screen.
Also note, orders placed before the upgrade will need to have links updated before you can download again. But you’ll get instructions for how to handle that if you try to download a PDF using an old-style download link.