I have been on Lamictal, 300 mg and Ritalin for my ADHD, and it has worked wonders for my mood, so far. This tiredness does not feel moody, more like an existential exhaustion.
Not really surprising after so many years having both ADHD and bipolar as obstacles to a normal life.
But yes - I will talk to my pdoc about it next time. Sounds odd: I feel fine, but tired of life.