Hi Anna,
In order for your shop to be succesful you need to get customers into your shop. Think about who you are targeting, what kind of ads you are investing in, how you choose the people you want to target, where you want to advertise, etc etc. A good start can be our selling guide: Selling Guide - The Spreadshop Blog
Posting a link on social media and expecting all these people to buy your clothes won’t do it. You really need to think about HOW you want to market your shop and also invest a little into getting people into your shop. Unless you of course already have a massive amount of followers who are all eagerly waiting for merch Sales won’t happen over night, one needs to put in some effort!