Hi your site is nice. Because I do a lot of work on my site is an article directory, I use a big monitor. Because your site is fluid width the text stretches to the width of the whole screen and makes it a little difficult to read but for people who use ipads and laptops, it should be OK.
It has happened to me when I was messing around my site. Mine was something to do with the sidebar width or the main content width – can’t quite remember now. It should all add up to the width of your site. Don’t forget the padding and margins as well. I think when it goes over, the sidebar goes to the bottom. There may be other reasons but this was my experience. [signature moderated]