Here's a picture of what I'm seeing.

When I click on them I go back to "Your Shops" and only see one shop. Does anyone know why this has happened?

The shops and galleries were transferred to a new system several months ago. I see you have one new shop, and 3 old ones (with the exclamation marks next to them).

You can find more info in the following thread, on how to transfer them to a new gallery etc. New Shop Guides

where could you create a gallerie?

go to the 'your shops' page under the commerce tab dropdown. on that page is a 'create a shop' section under which you can create a new shop or gallery - just enter a name, change the dropdown button that says 'shop' to 'gallery', and click 'create shop'.