No posts showing up in many themes

I set up my website with the 2013 theme. It had some widgets and links and other things. As of yesterday, when I put a new blogpost up, the website only showed the headline of the new post without any of the content or any of the older blogs. When I changed it to the simple catch theme, the blogs would show up again. While I am a bit of a luddite, I was doing fine with this before. Any suggestions on how to fix this would be very helpful.