Adobe documents acting like images - won't let me add text, forms, etc.

This issue began a week or two ago. I use adobe all the time for work, and I've never had this problem. I have always been able to 'edit PDF' and 'add text' even if the original document was a scan (ex: a fax that was received).  I've used this method to complete forms so that I don't have to waste time and paper by printing, completing in pen, scanning, etc. 

However, over the past few weeks when I have attempted to 'edit pdf' and then 'add text', the document acts as though all of the current text (aka, the form I am trying to fill out) is a picture. It won't let me add text on top of this 'image', but will only select the image. 

This is happening across the board, whether it's a document that someone has scanned to me, faxed to me, or something I 'print to PDF' myself. This is not document specific, except that it has become all PDF documents. 

Why is it doing this, and how do I tell it to STOP converting my documents into pictures, or at least allow me to add text on top of them.