Yes, both are different.... the first sentence is more apt and make more sense. I dont mean that the second one is wrong.
Worried means you are concerned or feeling uneasy about that matter. Upset means your current emotional state that you are unhappy. "Upset" is a more stronger case of unhappiness.
Well I would say their is a difference, because you don't have to be upset about something to be worried. You might be glad that you're being fired but just worried about what to do next. So yes in my opinion their is a difference. Hope I helped