ok i had my slave cylinder replaced about 4 months ago and then i replaced the hose with the SS one from mazdatrix. recently i've noticed that my clutch fluid has become black and today i was driving and lost all clutch pressure. I'm assuming i have to replace my clutch master cylinder since the other two parts are only a few months old. am i right with this? or could there be something else? thanks!

 

Yes, you should always replace both and the line when one or the other needs replacing.