Why does one feel constantly depressed?

As-salaamu-alaikum Mufti
Muftisaap, I need some assistance, alhamdulillah I read my 5 salaats with jamat, I make daily zikr, read quran however I constantly feel depressed, I am married with children, no real issues but I constantly feel sad and make dua that Allah must take me away, what can I do to feel bette.
Jazakallah