If I am covered under medical and life insurance at work, is it still necessary to have another life insurance ?

Absolutely.

Usually employee benefit plans end when you leave the company. This means voluntary or involuntary.

Insurance is supposed to give you peace of mind and remove risks.

Relying on a employer provided policy may keep you worried and leave you uninsured without you planning for it.

It's always a good thing to have policies that you own as well.