I donno what happened but I added a page break to one of my articles (to split a large article into 2 pages) and then when I clicked preview the website had lost its styling, as in it looked like a mobile site. but ONLY when I log in.
I've tried using a different browser, and it worked fine, until I logged in through /wp-admin and then it was messed up again. I also tried resetting the post back to a previous revision before the page break was added, but I still have the problem. Any ideas???
Here is a screen shot in case I didn't explain clearly enough:
http://thestupidforeigner.com/wp-content/uploads/2013/07/website-screenshot01.jpg