Countdown alerts until deadline

Hello guys,
I've been searching throughout this forum and cant find any answer, i need help.

I want to make a 14 days countdown alert until my deadline. I want a running countdown showing "14 day(s) left" "13 day(s) left" "12 day(s) left" "11 day(s) left" "10 day(s) left"...................."2 day(s) left" "1 day(s) left".

so, everyday when I open my project tracking list, I can see how much days left to follow up my projects to meet customer's deadlines.

Also, if possible, i need the cell to show "TODAY DUE!" when the deadline comes.

Here I attached example for you guys to refer. It been weeks, I'd been trying hundreds of formulas but still cant find any solution, please help me.

YOU'RE AMAZING!!!!!!!!!!!! thank you very much, i should have came here before, my whole week wasted bcs im stuck with this. THANK YOU VERY MUCH IT WORKS VERY WELL JUST THE WAY I WANTED TO