ckeditor weird output!

Hello everybody!
I've ckeditor drupal module 7.x-1.14 with ckeditor version 4.4 installed on my website. the installation was easy, but there is a big problem here. when i add my content to the editor and styling different parts of it ( like fonts, colors, underlined and etc. ), after saving changes, none of my styles are applied! ( i use full html filter for adding content ) here is an example :

I type in my editor : " hello! such a nice day. "
and make the "hello" word "bold" and the "nice" word "italic" and give the "day" word a font size of 36 pixels. but when i save changes,
i get this result :

[b]hello[/b]! such a [i]nice[/i] =36pxday

In other word, what i see is not what i get! :) I don't know what am i doing wrong. i've tried many things ( including re installing ckeditor ) but none of them worked. any help would be greatly appreciated.