Unfortunately, a negative routine EEG does not exclude epilepsy. If the cause of the spells are still unclear, I suggest you pursue a video-EEG monitoring study at an appropriate facility rather than a sleep study, since the latter usually is inadequate to diagnose seizures. Any anticonvulsant may cause problems with sedation, concentration, memory, and Tegretol is no exception. The best tolerated medication depends on the individual. Fortunately there are many other new medications that can be used instead of the Dilantin or Tegretol that you have had difficulties with.
Stress is a common exacerbating factor for epilepsy in many persons.