What’s the difference between eustress and distress?

Eustress is positive stress.
Distress is negative stress.

Distress lowers your work performance, gives you negative feelings and overall discomfort. Distress can last for a long time or for only a little while.

Eustress actually helps your work performance, gives you positive, energetic feelings, and can motivate you. It usually only last for a short term.