You might actually be ok with the Modafinil, then. The reason it screws up BCP's is because it alters how quickly the liver processes things.
So the Modafinil makes the liver process the BCP faster--your body gets less of the hormone--the effect is that you feel like you're not even taking your BCP.
If you aren't adding any hormones...then it doesn't matter that the Modafinil is speeding things up. You lucky duck, you!
I did have headaches with the Modafinil. I have Delayed Sleep Phase Syndrome, and we were trying to use the Modafinil to get me functional earlier in the day, and then hopefully I'd be tired enough to sleep at an appropriate time. The only thing that happened was that the Modafinil allowed me to be functional at 7 or 8am, I'd get tired late in the afternoon, and then get my "second wind" as usual and be awake till 3am. This went on for 2 weeks. Unfortunately I also have night terrors and sleep walk--stress and sleep deprivation bring them on. So going for that long with out sleeping...I ended up waking up one morning in the stairwell with a 1.5" splinter in my hand (from the banister).
Ritalin side effects were...well...good! When I take it I feel VERY awake, and an increadible need to be productive. Unfortunately again it did not alter my sleep/wake cycle. The DR felt more comfortable letting me go back to Ambien (so that I am at least getting 8 hours of sleep to prevent the sleep walking). I have an appointment with a sleep/wake specialist in mid Dec and a sleep test as well.
We shall see ::steeples fingers::
Here's a great board to find out more about sleep issues: ok I can't seem to post the url (I don't have 15 posts), but it's talkaboutsleep dot com
boards as well as general information.
Good luck!