You have asked the right question and I will give you a candid answer. All of the drugs you are taking have a powerful effect on the cns, so any combination could have caused the seizure, and coming off some of them will have to be done carefully, because coming off can also cause seizures.
Neurontin, in this case, may be a good choice as a both a mood stabilizer and a seizure control medication.
If I were you, and would make myself less dependent on the magical pill combination and work closely with a psychotherapist to understand your stress, anxiety and depression response to the challenges in your life. That will help you more than anything. If you are hesistant, or can't afford a therapist, you can start your work inexpensively on my online therapy program at www.masteringstress.com.
Thank you for your help - I am familiar with your website and love it! I have also been in intensive therapy for 6 years. Q. I have an eeg coming up tomorrow, should I remain on all medication when I have it to see what my day to day state is like (i.e. should I take my adderall dosage that day), or should I try to go in un-medicated?