Position Closed

PEPTIDREAM slid by 1.68%, going below the \5K line.

I closed my buy position at \5K in the afternoon session.

What is the lesson I need to learn from this?

Was it too early to close or too late to close?

Compared to the closed value on Wednesday,
I lost almost three fourth of the profit I had
but the good thing is I still made a tiny bit of profit out of it.