I have never used ads and showcase myself,bu I have seen many comment that it doesn't work well,unless they are selling items for a given holiday,and they promote during said holiday.
You're still fairly new,so don't worry too much.I had this happen too,I got several hundred views a day for a few days,and now I mostly get only 20 or so.Views ebb and flow.
What you can do to help your shop get seen,is promote yourself on places like Facebook and twitter,not paid promotions,but start a shop page on FB and get some likes for it,and so on,maybe start a contest for added interest.
Also,I haven't looked at your shop yet,so I dunno if you're doing any of this or not,but make sure to have descriptive titles for your items,and be sure to use all of your tags,but don't use simple one word tags.Ex for me:Tail,animal,costume.These tags would be very vauge,and I didn't get many views from them,but something like animal costume tail as a single tag,has helped much more.Optimize your tags,titles,shop announcment and titles,and item descriptions for SEO,which will help your shop and items get noticed more by search engines.Take clear photos of your work,clean backgrounds,such as white ones,tend to be helpful,and always use natural light,and be sure to use all 5 photo slots.And lastly(that I can remember)is make sure all your policies are filled out.
All that aside,the more items in your shop,the more likely you are to be seen.Good luck to you :3