Changing home directory wiped previous account?

Hi all. I got a new MacBook Air last week, and had it all set up. Today, when I was looking at my user settings, I decided that I wanted to change the home directory tab to my nickname rather than my full name. I simply typed in my new name for it, and pressed save. I was prompted to restart my computer, and when I did, it was as though I was starting up a brand new computer! I had to re-do all the set ups as though I was just opening my laptop for the first time. Nothing was left on my desktop, but when I went to my previous logged in websites, all of my passwords stayed saved. What is going on? Did changing my name remove my entire account? I find this hard to be the case because so much of what I had done had been retained. Is there any way to access my old account? I just don't want to have two of the same accounts, I don't know why it seems I've now created a new one. Help would be great, thank you!