Crash while populating

my website’s meant to be going live in the morning and we’re pulling an all nighter getting the content uploaded – or we were. The website has suddenly crashed. My web developer is unavailable and I’m not really techy. Any thoughts would be very welcome.

The message is “Google Chrome could not load the webpage because hartlepoolfolkfest.co.uk took too long to respond. The website may be down, or you may be experiencing issues with your Internet connection.” Till a minute before this we’d been uploading content for hours with no problems.