Why did my products disappear from my online store?

[wikioki]

I'm currently setting up my shop in developer mode, hoping to soon make it live. 
I had 16 products in my store.
I added 16 more today, but suddenly now I only have the latest 15 products.
the rest are gone.
I checked in the admin/products
I checked the drafts
and I checked the filters, collections
They are just not there anymore!
Even the images related to the products are not there.
they have been deleted

[StephensWorld]

I'll chime in, since no one has responded yet:

My first instinct is that you're probably working on 2 separate Shopify stores by accident. Check the URL at the top of your browser when you're logged in to the Shopify admin, and make sure you're working on the same Shopify store each time you're logged in. You can have multiple Shopify stores linked to the same login, so if you're mistakenly working in different stores each time, that would definitely explain the issue. 

When you're adding products, make sure you're "saving" before moving on to the next one. 

If you have anyone else listed as a 'staff member' on the store, check with them to make sure they're not removing things. 

If you're using an app/API to migrate or import your products, there could be an issue there too. 

TLDR: Products don't just 'delete themselves' within Shopify. It's something you're doing - either working in separate stores, mistakenly deleting things, or working with a broken/glitched app or API integration. 

[wikioki]

Thank you for the reply.
The issue was that 2 different products had same SKU. So Shopify was replacing the other ones. 

[StephensWorld]

Shopify doesn't delete products if it notices two are using the same SKU.