What I understood is that you can feel weak only until the moment someone else starts to feel weak as well. Especially if one is close to you.

At this very second you accumulate all the energy you have and you try to support one and cheer him/her up. Especiallyx2 if you both are sad about the same thing.

And suddenly you feel power to become a savior for someone even though your own savior didn't manage to show up.

It's all about changing the roles.