Lamictal isn't, but maybe the Abilify? I do not know much about Abilify, for I haven't been on it or know anyone that is. But Lamictal for most, including myself, is not sedating, you can take it and still carry on daily life, even work with machinery.
Having a baby, is probably the most likely cause of your fatigue, which over time (quite awhile), providing your hormones adjust, you'll feel less tired.
Then depression can be another thing, if you get bouts with it, can knock you out.
It's always best to take such things up with your pdoc and gp, maybe they can either help you with med changes, dosage or new, or add having a good physical to be sure to rule out any underlying health problems.
I wish you lots of luck with this, and congrats on the new baby.