I'm on Seroquel too, but a much higher dose. Usually, that knocks me out, but I am also on Clonidine for sleep along with melatonin. I used to take hydroxyzine & Trazodone (hydroxyzine to fall asleep, Trazondone to stay asleep, but it stopped working).

When I was trying to get pregnant, I kept psych meds at a minimum and combined Valerian & melatonin for sleep. It's not recommended to combine the 2, but it was the only thing that worked for me.