We are switching me from Tegritol XR (regular tegritol tablets didn't work as well) to Lamictol for side effect and health issues

For the first 7 weeks of wiening Lamictol (regular tablets) worked just fine... however on the 8th week when I went from 1000mg of Tegritol XR a day (400am 600pm) to <600mg pm, and taking 150am 150pm of regular Lamictol I began to have significant siezure issues. (No siezures, but it came close!) I uped my dosage of Lamigtol (didn't work) then I changed to Lamictol XR 200am and 200pm... and over the course of 3 days it worked!!

However, I am uneasy and nervous because I have heard it is supposed to be a "Once a day" pill... and I am not only taking it twice, but I am still taking 400mg of the Tegritol XR... which is supposed to have a lower effect due to the Lamictol XR

Will this continue to be a good experiance???
Should I be worried???
I have been siezure free for 19years on Tegritol XR... but it came close the other day to ruining my life... Will Lamictol XR be as effective in the long run??

Sincerely,
Faith in Lamictol XR/Lamictol been shaken.