I've been having this same problem, and would be interested in knowing how long to expect this tired feeling to last. I know everyone is different, but if I knew an average amount of time before that energized feeling kicks in, it might help me make it through. I'm starting my second week. Not only do I feel tired, but kind of sad as well. I played a singles tennis match yesterday for my team, and I could barely make it through the second set. Thanks.

JJ