Is there any way to go back to my macbook's setting prior to me stupidly messing with the "user

Is there any way I can go back to my macbook's old setting before I stupidly changed the "Users & Groups" setting; or did I just lose all my school work and my children's pictures for good? I was trying to sync my Macbook with my iMac that I just got so I was changing the name to match each other, but then when it restarted, it's back to default settings with none of my work and my children's pictures. Please. Can anyone advise me? I do not need an insulting comment. I already feel stupid enough.