It does sound like there may have been an attempted hacking. Check your bank account and credit card. You should have gotten funds for the sales. It may be a huge prank by someone who knows your password.
The other is a Etsy glitch. I've not heard of this happening before so I would think that a power outage or search or cascade effect from something Etsy was doing accidentally opened your account. I doubt Etsy would do it deliberately.
Contact Etsy to find out.
It's one reason to have the messages forwarded to your email so you know if something has gone amiss. I use the emailed messages as a backup when I am away from my shop for an extended period.
