Why, there is certain difference between being angry and being upset. Anger makes one to shout, to fight, while being upset rather to cry or to whimp [in the corner ]. Another (or just close in meaning) word for upset is frustrated.
But anyway I believe you should take care of tenses, i.e. it's better to say either "Iam upset/angry because you don't call me" or "I was upset/angry because you didn't call me"