Upset usually describes feeling unhappy, disappointed or sad. For example: I’m upset that I missed my flight yesterday. Uneasy is used when you’re feeling uncomfortable or anxious. For example: Walking in a street without lights at night makes me feel uneasy. I hope this helps.

They are very similar words. Upset is a very broad word for negative emotions. Someone who is sad, angry, or afraid can all be described as "upset." Uneasy usually is a slight fear, often of something unknown. But there's a lot of nuance in these words. If you can give more context, we might be able to help more with the specific nuances.