As well as refuelling during the day and after your evening run, you should make sure you don't work too hard, especially on the way in to work in the morning. You've stepped your mileage up by a significant amount and your body is probably still adjusting. There will be times when your reserves are depleted more than you can recover during the day, so if you are tired, accept it and take it easy until you are feeling stronger.
Take it easy? I laugh in the face of tiredness! (or giggle quietly at it... until I get to Eltham Hill which usually wipes any smile from my face...)
Seriously though, you do make a good point.