Lamictal saved my life. I am Bipolar 1 and went into a very deep depression that not one psychiatrist could pull me out of. I had been on every med you can think of. I was admitted into the hospital for mixed episodes and had a young psychiatrist assigned to me while I was in the hospital. He stopped all of the meds that I was taking and put me on Lamactil-200mg- and wellbutrin 300mg. Within 3 days, I was a new person and have been on it since. For me, it is a miracle drug. I did not have any side effects.
Yes this type of reaction to Lamical is rare but changes like you described can occur when adjusting medications as what they are treating can return until a person reaches a full dose. However only a psychiatrist would understand the clinical specifics. The best thing to do would be to discuss this with your psychiatrist and also to keep a mood tracker so you can see how things progress over time and print out the results for them.