Thanks for using the forum. I am happy to address your questions, and my answer will be based on the information you provided here. Please make sure you recognize that this forum is for educational purposes only, and it does not substitute for a formal office visit with a doctor.
Without the ability to examine and obtain a history, I can not tell you what the exact cause of the symptoms is. However I will try to provide you with some useful information.
It is difficult to address your post without knowing more history of the seizure and your background. However, there is a condition called nonepileptic psychogenic seizure (sometimes referred to as pseudoseizure). These events are paroxysmal. What really determines them from epileptic seizures is that these types will not have EEG changes when the event occurs. Have you had an EEG during an episode? Additionally, studies have shown that up to 40% of these patients may also have true seizures. This is what makes this diagnosis so difficult. These seizures are more common in young females. They should not occur during sleep. Has your physician actually seen an event/seizure? If not, it may be worthwhile to record an event and show him/her.
The treatment of nonepileptic seizures does not include medication. The mainstay of treatment is psychological therapy.
I mentioned this episodic disorder partly because you mention the history of bipolar. However, please know you can also have true epilepsy and bipolar. Have you had a recent seizure/event?
I suggest you follow up with a physician to discuss your history.
Thank you for this opportunity to answer your questions, I hope you find the information I have provided useful, good luck.