Seroquel is not intended to be used for
sleep, it sedates people as an unwanted side
effect and so the manufacturer sold it for
that purpose (illegally, by the way, but it's still used for that). It is possible your system doesn't like the combination. And as I said, if you Google how Valdoxan works, it only works if it helps you sleep and if it isn't doing that to the extent you need Seroquel as well, it could be it isn't being metabolized well by you.