Hi Zack,
I had to read your response a couple of times, but it appears you
have done something to your blog -- in fact, many things.
- Added Bidvertiser PPC ads
- Changed the background
- Added pictures
All of these things may have an impact on the conversion rates because each element adds a new distraction or feel to the website. If you're solely trying to promote an affiliate product, then don't add any page leaks (i.e. PPC ads which allows users to click out of the site).
Also, the pictures you've added may not coincide with the ideas the visitors form in their head about the product being offered and neither the background. These are things to consider when making, even small, changes to a site.
Hope that helps,
~ Teli