I was very shocked to hear bad news today.

Today　I heard very bad news... (you don't need to repeat this sentence again)

It said The bad news was that my previous workplace has gone bankrupt.(workplace is one word)

I have had worked for that company for 6 years when I was a college student. (you must use had if you are talking about the past)

I loved my workplace, the owner, my colleagues, and the customers. 

The news made me so sad, depressed, and disappointed

I hope good things will happen tomorrow, because of the bad news I received today.

I'm sorry to hear the news about your previous workplace. I hope you made a lot of happy memories there. :)