Help! Google not Showing Blog Posts Anymore

In the past 3 weeks we have noticed a huge decline in the traffic to our blog. We used to have several blog posts that were listed on the first and second page of Google; and now many of those are not found at all. Instead those that we did find buried deep in Google; when we clicked on the actual link; it did not display the correct blog post that we had in WP. We have noticed though that the same blog postings that were once ranked so high in Google; are now appearing in Google results linking back to our Facebook page which happens to have our duplicate blog posts.
We did not change any settings in WP lately; and we are totally baffled as to what may have happened.

Here is the link to our blog: https://www.ronusa.com/blog/