Hi there and Welcome to HealingWell!
My mum took lamictal for a while but didnt get the racing mind thing. I know that a side effect of Lamictal can be insomnia... perhaps this has something to do with it? It is possible that you only suffer from 1 side efffect when taking a medication. It doesnt always follow that if you get 1, you will get 5 or 6. It might be worth talking to a doctor. Since idiopathic epilepsy has a good success rate with meds for control, it might be worth trying another one if you think it is the lamictal causing this.