My theme crashed

I was on the Themes page and it told me to update Customizr Pro’s theme. I updated and now it says that the theme it broken. It has reverted to an old theme. I had custom CSS- lots of custom CSS that now it looks like I’ve lost. This is not a child theme and I have not done anything differently. In fact, all the CSS worked just fine. When I try to load my site, all I get is a blank page. Help me now please. This is a business website and it is for a client and we need to launch it tonight. Thank you.