Do not search your or anyone else's username, do not view the site, stop giving this website attraction as this will likely drive the site to get more attention in the algorithm.
Please read the other's posts in this forum, I see constantly that no one is reading them so please, I implore you to.
No one is likely buying your art on this site, it is discouraging but please, take a breath, and take a step back. Take care of yourselves. Do not let this discourage you from selling your art or otherwise. Your work is worth it. Do not let this scare you but if you truly need to, set watermarks on for your own comfort but bots and data scrapers do not care as you can clearly tell through screenshots people have posted already. Just taking one look at the site is sketch enough for any even non-artist to steer clear of this.
With sites like this, they can earn revenue from clicking on links and domains sell for more money if there is more traffic to a site.
There will always be another site like this though we are not fully powerless to stop it and I would highly highly discourage the idea of sending your information to the site itself for DMCa, Cloudflare only, I cannot stress that enough. Even something like an email carries a lot of weight in digital information. Link is in the OP.
Unfortunately, yes, it is very likely your art is on the site if you post your art in anyway online
Here is a pretty informative post I agree with, though of course take it with a grain of salt as there is not a lot of evidence and is just speculation- https://dogtoling.tumblr.com/post/733891227217543168/so-some-random-website-is-selling-your-art-and
If Cloudflare gets enough information about the site they will likely take it down from their servers though this is likely a hydra situation as there are clones of the website already.
Important information I have gathered regarding the site, will likely update once more comes up:
DNS: Cloudflare ( https://abuse.cloudflare.com/dmca )
Website Host: Hetzner Online GBH ( [email protected] )
Registrar: TLD Registrar Solutions
https://lookup.icann.org/en/lookup