What do you do when you are so dead tired but you still have a ton of work to complete? Any advise on how to juggle work, deadlines and motherhood?

First of all, accept that you have to rebalance your work and life and that it's okay that you can't probably complete the same work amount than before. Your to work smarter to avoid working as hard as before. It's all about discipline and starting to say no more often and consciously than before.