Darker scene with directional light

Every time when I’m doing something with my project, directional light get’s weird, scene get’s darker light or sometimes get’s no shadow render, is there any solution? I was searching here for answer but got nothing.

http://i.imgur.com/pMNsfyz.jpg - this is what I’ve getting.

http://i.imgur.com/5DwOIAs.jpg - this is OK, like it should be.