Website Traffic

I'm not sure if this post is in the correct area...
and almost every place where I tried to create a message
--- I was told I needed to upgrade ? or a Jr Membership ?

Here's the issue:

I know it's difficult to give advice without seeing the actual website / url.

But please try.

I spent a month build a system on an affiliate API.
The API allows me to grab all pertinent info... prices, images, descriptions, etc.

I launched my website in November 2013.

Every month since then... so Nov 2013, Dec 2013, Jan 2014, Feb 2014
--- so total of 4 months...

My earnings have topped $600.00 a mth on Total sales of over $18,000.

Then all the sudden, this month (March 2014)... my traffic slowed to a crawl.
I am still listed in the search engines - but I cannot find my site in the top 10 pages.

4 days ago... I was on page 1. Every day... for 4 months.

Before, I was doing about 25 to 30 sales per day.
I'm doing about 0 to 4 sales per day now.

Can someone please me what the hell I did wrong...
as well as what's happening ?

Much appreciated.

google probably detected or reviewed your site and determined its value is not worth its position in search.

too difficult to give you tips without knowing more about the site but i will give my two cents :

- check webmaster tools for any manual messages or site wide spam etc
-check webmaster tools for any crawler errors, site access issues etc
- check your analytics for obvious spam referrers etc
- check you backlinks for any bad neighbourhood links

You get the idea..dont panic..start from ground up to see if you can find anything
-