Layout in browser is different to Upfront editor

I've been making a few tweaks to my site, all seemed ok, checked this morning and things are all over the place in Firefox, Chrome and IE. I use the editor in Chrome and it looks totally different to the preview version in the browser. I'm using W3 Total Cache and have cleared repeatedly. I removed some of the changes I'd made to yesterday and it still won't go back to how it was. Things like width:auto and height:100% on the main slider on homepage. Creating a second Facebook icon in the footer. Testing different z-index values on come elements. I also noticed that hiding the Facebook icon on the mobile responsive version hid it from the desktop version too.
Please can you give any help as to what the problem might be?