"Error establishing a database connection" (but that's not all)

Hi, I made the mistake of changing the home url, initially it was http://shaneynayguns.com/wordpress and the site url was: http://shaneynayguns.com/wordpress too. I then changed the site url to http://shaneynayguns.com (thinking that that will make my site go live, as you can tell I’m an absolute idiot at this). Nothing happened, so genius here, changed the home url to shaneynayguns.com. That’s when things start to go awry: I couldn’t log in to wp-admin anymore and going to .com/wordpress redirects me to an error page. (shaneynayguns.com remain unchanged and directs to a landing page) I then went on on this forum and followed the exact instructions which were:
1. go to phpmyadmin
2. go to the correct database
3. browse wp_option
4. edit site url (I changed it to .com/wordpress)
Apparently based on everyone’s comments, it worked for all of them… except me! shaneynayguns.com/wordpress now redirects to a page with “error establishing a database connection”! It’s driving me mental! I was hoping if any of you could help me with this. As is obvious, I have not a clue when it comes to web jargon so I would really appreciate a simplified solution. Yes I’m an idiot, and I terribly need help! (F.Y.I: I host on godaddy)
Thanks in advance!