It gets progressively more physically demanding, Much more if the baby has health or other issues.
I used to get heavy migraine attacks, I could just shut myself in a room go to sleep and recuperate. Now I pop couple or even three ibuprofen to get by.
This advice is almost always good regardless of circumstance.
Achieving and maintaining a healthy weight, and being fit enough to care for yourself and others as long as you can, are life-changing decisions for the better.
Once you get more energy, things will fall into place. So keep that as your first priority.