As you yourself say, you are not happy. Being sad is a state of mind. When the sadness is significant affecting daily routine functioning and over a long duration, it becomes depression. Getting angry is a way of expressing one's sadness. If you're getting suicidal thoughts, it is high time that you see a Psychiatrist urgently.
Next Steps
Psychiatric consultation as early as possible.
Health Tips
Avoid being alone and acting on your impulses. Seek medical (psychiatric) help immediately.