ConfusableEnvy or jealousy
Wanting something that someone else has.
I envy her confidence.
Worry about losing something you already have.
Rohan felt jealousy when his best friend sat with someone new.
Remember: In everyday speech people often use jealous for both. In careful use: envy wants what others have; jealousy guards what you have.
Quick check
Rohan felt ____ when his best friend sat with someone new.