Can login, can’t get anywhere else

I’ve installed WordPress on my site and all was working fine. Then it stopped. I can login, but any other page beyond the dashboard results in the “Error establishing a database connection.”

I’m trying to recall what I did just before it stopped working. Not sure what section I was in, but there was a space to enter in the wordpress URI and the web site URI. I had my wordpress URI set to http://shannonentin.com/phat/ and my web site to http://phatmommy.com. These are the same, so I tried to change the shannonentin.com/phat/ to phatmommy.com. Could this be why I can’t access anything?

Any advice would be MOST appreciated! Thanks!