Switching from manual DNS settings to Nameservers with Network Solutions

Our domain is with Network Solutions and has been connected to our Squarespace website for about a year. Two days ago, I found that our website was not working (under construction message) and saw a DNS error message through my Squarespace account. I saw the new nameserver option instead of manual DNS settings so I entered the nameserver information into my Network Solutions account. There is still a DNS error message in Squarespace, the website is still down, and now our emails associated with the domain (Google-based) are not working. Is this just a part of the process of switching from manually imputed DNS settings to nameservers? Is it OK to do what I did? I couldn't find guidence on making this switch. I could only see nameservers recommended when a website is new, so I hope I haven't really messed things up! I was not expecting the downed email.