Taking It's Toll

The long days in kindergarten are taking their toll on our son. By Friday he was exhausted, over-emotional and a bit difficult. His teacher did thankfully recognize he was very tired and related his unusual behavior to his fatigue. But how do I give him more energy? How do I take away the sinus headaches that have been returning this week? I did the only thing I can do at the moment, thanked her for her communication and understanding and expressed I will do whatever is in my power to help him adjust. But I feel powerless.