Google ranking Drop - Need suggestions

I have recently experienced a major Google ranking drop and and can't quite figure out why and was hoping that maybe some of the experts in this forum could help me out.

My website is Wordpress based and is running the plugin Wordpress SEO by Yoast. It was preforming very well at first when I was publishing articles (always in the first page atleast) and now some of my articles aren't even in the top 100. A majority of my articles that were raking very high aren't in the top 100 results anymore.

If I go look on bing and search for the exact same thing then I find that my site is ranking very well, first page or even the first result.

I write a lot of product reviews on my site and then include affiliate links at the end of the articles giving the readers a place to buy the product if they have an interest. When I first started writing these articles I wouldn't include the "rel=nofollow" on the affiliate links. Since I have taken the google ranking hit I have since went through my articles and edit the affiliate links to include the "rel=nofollow" tag. This was a few days ago and I have not seen an improvement.

Also a few days ago I added some 125 x 125 ads in my sidebar that I also didn't include the "rel=nofollow" tag at first and I have since corrected to add the "rel=nofollow" tag.

I am not quite sure what else I can do to help my SEO with Google. Bing SEO seems to be just fine though that doesn't really matter to me because more than 90% of my traffic comes from Google search.

Any help would be appreciated and I am open to any/all suggestions.

You can view my site at www . actionfigurefury . com