Help Please Weird Scroll

http://iccitcouncil.com/thecasserole/category/fiction/

This is my site. I am making a child theme of 2014.

I am wondering why when you scroll down, at a certain point everything jumps down and the nav bar disappears.

Also don’t know why on pages the lefthand sidebar is slightly moved over from where it is on single posts and archive pages.

Please help 🙁