Lamictal, isn't sdeating, perhaps it was the other med, that made you tired?
I've been on Lamictal for about 3yrs or more for Bipolar-II,other than Lithium, all others were very sedating. I found Lithium and Lamictal non-sedating, allowing me to function,drive, and work. Switched to Lamictal cause though it's a mood stabilizer (anti-convulsive) it has anti-depressant qualities. I started with Concerta, too, last fall, this helps my ADD I also have, perfect combo I'm on now, Lamictal and Concerta.
I wish you luck with this.