It is a mental illness that causes people to be unbearably sad, along with other things, like more anger, eating less, and possible suicidal thoughts.
loosing interest in every thing is the symptom.if your mind got hurt continuously then it will end up in depression. no need to worry. few weeks or month u will become introvert but that timeperiod is essential to improve ur mind tolerance and mind power. so depression period is necessary in your life. ,Suicide thought is the final stage .In that case u may need to consult doctorHow do i explain depression?