The antonyms for "un-stressed" are "stressed," "worried," "anxious," "tense," "burdened," and "pressurized." When someone is "stressed," it means that they are under a great deal of pressure, anxiety, or strain. Stress can be caused by numerous factors such as work, family, financial issues, and health problems. People who are "worried" or "anxious" are also experiencing negative emotions that can lead to stress. Someone who is "tense" is often physically and emotionally strained, while someone who is "burdened" is weighed down by problems or responsibilities. Finally, someone who is "pressurized" is experiencing pressure from external sources, such as work or personal relationships.