Multisite installation problem

I am new here and unfortunately, I did something wrong that I don't have a clue if it is recoverable...
I wanted to test hosting and I thought that I had my chance to also test a Multisite Installation for first time, since I only have experience to the Standard WP installations the last 4 years!.
So I created an account to Cloudways and I Installed a WP MU application on my server, 10 days ago.
All these days I did not set up my Network. Instead I was working on my core site installing and setting my theme and plugins according to my basic needs. I created a few pages and uploaded some media.
Today, I decided to follow the instructions of your "Ultimate Guide to WordPress Multisite" post and I went to "Settings" Network, and I followed the steps, assuming that I was creating a subdomain, new site.
After that, my previous work disappeared! I can only see the new site, under my main domain name and everything is new, except of the plugins and themes I had initially installed.
Is there any chance my initial work to exist somewhere?
I have only database backups but I not at all full files backups..
Please advise, since Multisite is a new area for me and I would really appreciate your expertise.
Thank you in advance!
Fotini Kokkinakis.