There are several things that come to mind here. The first is that it makes sense you would be tired after suchan early start, a workout, a full day at work etc. So I think the best thing is to start to accept you are human and that being tired is a healthy sign.
Secondly I would pay attention to the type of food you eat through the day making sure your snacks are high in protein. This will often even out your energy flow and not create drops from a more carbohydrate intensive diet.
Thirdly I would find a time to take a 20 minute power nap or learn how to meditate. Both of these can have enormous benefits.
Good luck and let me know what you find. I am very interested.
