Hi there,
It may be the Seroquel more than Lithium, that is causing you to feel wiped out. I personally prefered the Lithium over the Depakote I had first been put on, the Depakote use to wipe me out, barely staying awake.
The Lithium did not do this, I was able to drive, function regularly.
My suggestion like I tell everyone is to contact your doctor, and see if adjustment of meds may be necessary.
I wish you lots of luck with this, and don't give up often it takes time to hit on the right combo.

Take care,
DE