Re: Complicated...Complex
"something complex may be well-organizedand logically constructed as well as subtle andintricate, while a thing that is complicated will have something irregular, perverse,asymmetrical in addition to fundamentalintricacy; complex is more formal and technical(a problem in mathematics is complex) while something like personal life can be complicated"
That's what one of the online dictionaries says about the difference between the 2 words, but in practical terms they mean the same.
I'm not a teacher of English, but I have spoken it for (almost) all of my life....