Does a thesis have to have a "Discussion" chapter? I have written a thesis seeking to analyze the ideological thinking of a newspaper through its editorials in a political situation during a certain period of time (1985-1991). I couldn’t count on my advisor and I have written my thesis by myself. My advisor approved my thesis and I must defend it in three weeks.

I have been reading other similar theses. I have realized that most of them use a chapter for “Discussion”. My thesis does not have such a chapter. I wrote a chapter for “Methodology”, another for “Results” and after that one for “Conclusions”. I am afraid that in my defense someone will ask me why I did not write a chapter for “Discussion” and I don’t think I have a very convincing answer. How would you answer to that kind of question?
Do you discuss the results and their implications?  Do you present the insights and conclusions?  Do you make your argument and present your evidence in a logical, persuasive way? 

I find that chapter/section headings are much less important than the overall document strength. If your thesis fits the following, the I'd defend it.  Worst case you may be asked to restructure; best case you make your point and it is accepted as is. 

Key Points: 
Thesis should 
- be organized and logical
- clearly articulate the main points and supporting evidence
- discuss any conclusions and insights

I'm sure there are others.  Section/chapter headings are author's choice - use what you need to accomplish your purpose.