First of all, I’m glad there’s finally someone who says “I messeed up” and doesn’t blame IE for this. Doesn’t happen often :)
Anyway. Reason why it looks like that is because you use HTML5 tags (such as HEADER and SECTION) that IE8 doesn’t understand. Including the [Modernizr script](http://modernizr.com/docs/#installing “Modernizr script”) in your HEAD will solve a lot of stuff I’m sure.
You’re using HTML5 elements and not an HTML5 doctype. I’d suggest changing your doctype to HTML5 and then you’ll need to add in something like [HTML5 Shiv](https://code.google.com/p/html5shiv/ “https://code.google.com/p/html5shiv/”) for the older IE browsers to pick up on the HTML5 stuff. IE8 and below doesn’t support HTML5 elements like sections, nav, footer, etc. without something like Shiv.