Installed new blog in folder, overrides main blog

I’ve been using my domain for the last few years, without problems. A year ago, I decided to install WordPress into my site, and I did so, also without problems. The address to this blog is https://www.jennynb.com, and the WordPress files are installed into the root folder. Recently, I found out that I needed a new stand-alone blog, and I decided to install it into a folder. The folder lies within the root folder, and is called “spania”. This went successfully, and the address is https://www.jennynb.com/spania. This blog uses a completely different theme, and the administrator, dashboard, etc. isn’t connected in any way to the other blog. This worked fine, until I decided on making one more blog. This time, I made a new folder called “art”, just like I did with “spania”.
However, even though the install went successfully, I wasn’t able to log in. Whenever I entered the log in information I had made while installing, it would just redirect from “www.jennynb.com/art/wp-login.php” to “www.jennynb.com/wp-login.php”. I was about to give up, when suddenly I logged in successfully. I installed a new theme, and started configuring my new page, when I suddenly realized that somehow I was logged in to my root blog, “jennynb.com”. When I entered the address into the address bar, my new theme showed up, without a single post aside from “hello word”, and nothing of my previous content. In a desperate attempt I tried to remove the new page, by deleting the whole “art” folder. (All the time using FileZilla.)
Still, this haven’t helped a bit, and I’ve ended up with the new art page overriding my entire old blog. I have no idea what to do in order to fix this, and I’m really scared I might have lost all my previous posts, comments, design, etc. How can I redo this?
Is there any way to fix this?
I’m really, truly grateful for all help! Please help me!

-Diva