Debbie, congrats on being such a successful shop! I would keep at it, I heard February was a rough month for lots of shops.
Mireya, I took a look at your shop and I have to say, I don't see the purpose and function of most of your items. I also sell graphic goods and you really have to market your items in a different way than other sellers. Using the term Printable or Custom Printable really helps in people understanding what your items actually are. You would really benefit from using real photos of your work instead of the digital renderings. I have found that customers want to see the product in it's final form, even if they are only buying the digital file. Make sure your audience knows HOW to use your products, you can't assume that they already know what to do with them.