How are the carbs? If you are getting enough good rest (?) then the tiredness may be a sign of hypoglycemia. It does not take the huge sugar rush then fall for everyone; even a little too much carb can send some of into hyposglycemic reaction. Lot your food for a few days and see if you find a connection. Hope you get to the bottom of it.
This time, like all times, is a very good one, if we but know what to do with it. Ralph Waldo Emerson
Any given day you are surrounded by 10,000 idiots. Lao Tsu, founder of Taoism