Auto-populate text based on value of two columns separately

I'm trying to figure out how I can change the text in Column E based on Column B and Column D. I have only been able to use the IF function based on Column D. But what I really need is:

If there is nothing populated in either columns B and D, Column E shows "Past Due".

Then when a date is populated in Column B, Column E show "In Progress".

Lastly, when a date is entered in Column D, Column E shows "Done".

And if not, any other ideas on how to keep track of progress without having to use a drop down box? Any help would be so appreciated!