Extremely low energy/ weakness?

I do graveyard shifts 1 week out of 3. It is killing me. I noticed that when I'm on those shifts I feel extremely weak, with no energy. I can't even climb the stairs to go to the break room in a single go. I have to take a break cause my legs just give in. It's like my limbs are made of jelly or something. Very weird. Also I get out of breath at every movement.