My old account and theme disappeared

Hi, I was using WordPress with Semplice theme to create my personal portfolio website. My old username is yunjieyao. I created the site locally on my computer. Today I was trying to connect the WordPress site with my Godaddy domain and host. Then after the connection, my Semplice theme in WordPress is gone. I cannot find my site any more.

I then tried to disconnect my domain with WordPress. After that my account disappeared. My old site cannot be found. My localhost cannot be accessed.

I’ve worked one month to customize the theme and add my content on WordPress so it’s super important to me. Is there a way that I can find my website locally on my computer? I’m not sure how things are working on WordPress. It would help me a lot if you give me any advice!