All good posts!! It DOES take awhile for your brain to get used to a particular dose. In my case, it can take up to one month. I too have partial seizure syndrome, and like you one aspect of my seizure pattern is that I get woken up at night in a seizure state. Not fun, and as you've found out it can be exhausting if it persists.
For me, my partial seizure symptoms occur because of what my neurologist terms "breakthrough." In other words, my primary medication (Dilantin) is no longer sufficiently controlling my brain's tendency to seize, especially during sleep. My breakthrough occurs almost precisely 90 minutes after falling asleep. When breakthrough occurs, and only when it occurs, I take a secondary drug. In my case, it's a 0.5 mg or 1.0 mg dose of Ativan (Lorazepam). The dose varies based on my years of experience of dealing with this. Typically, within 5-30 minutes after taking Ativan, my seizure symptoms subside. Ativan is a narcotic, so you have to be careful not to take a too much in total per day, otherwise you begin to tolerate it (meaning it doesn't work). You DON'T want to go to a secondary drug until you've explored the options with your primary drug in close consultatiion with your neuro, and found you really do need a secondary drug.
Good luck!!! 