You were a mentally unstable person, which has made you a person to observe in case you became a threat, so that's what Katniss did ever since she came to District 13. Observed you.

Her protective instincts made her observe you. She wanted to make sure you weren't a threat to others or yourself if you had a breakdown. Katniss stayed silent, watching you.

No one ever approached you, and you never approached anyone. Katniss also noticed you were always playing with something in your hands.