You are not alone. Thousands of smaller businesses that had occupied top natural rankings have been demoted by Google's recent algorhythm changes, which seem to favour larger companies and big brands.
The SEO experts's wisdom is that you need "interesting content", which means they will write blogs and articles that will get backlinks, and Google will promote your site again.
[ it costs a lot of money, and results are not g'teed ]
In my view the first action you should take is to check your website itself. Use Google Webmaster Tools to check your basics, like image titles and alt tags, and if you have duplicated titles, or pages the crawling bot cannot access. Then read Google Webmaster Guidelines, often and carefully. Then check feedthebot.com for more plain simple excellent advice, with FREE tools to check the effectiveness of your webshop.
Make sure your website is functioning as well as it can do, and if you can, write your own blog about your business to give added interest to your visitors.
Good luck, from a webshop owner fighting my way back!
