HELP!!!!!!!!!!!! Messed up my blog!

Hi the perils of a little knowledge but nowhere near enough… please excuse my idiocy.. I’ve just re-launched my blog and sent an email to a 1000 people and tweeted about the first post, then a friend of mine makes the innocent comment “Change the URL to /blog not WordPress. ‘ so like an idiot I go into Settings on the WordPress dashboard and change the URL to /blog and save the changes, now my site has lost all its formatting and even though I straight away re-entered /wordpress and save it in the dashboard its now saying saying not found on the directory. I also now cannot get back to my Dashboard

I’m desperate to set things back as they were because at the moment anyone visiting my blog gets the basic info but no theme: https://simondetreywhite.com/wordpress/

What the hell have I done and how the hell do I put it right? This is a PR disaster for me – re-launch blog then immediately screw it up..

Simon

thanks

Simon