No one should ever ask themselves that: why am I unhappy? The question carries within it the virus that will destroy everything. If we ask that question, it means we want to find out what makes us happy. If what makes us happy is different from what we have now, then we must either change once and for all or stay as we are, feeling even more unhappy.
It is always important to know when something has reached its end. Closing circles, shutting doors, finishing chapters, it doesn't matter what we call it; what matters is to leave in the past those moments in life that are over.
When you cease doubting, you have stopped moving forward.