Hi Jane,
Is the Valium you take specifically to help with sleep? Or anxiety? Or both? If just anxiety, perhaps your doctor may consider switching that to the morning or even afternoon. I find with 1mg Ativan (lorazepam) it helps knocks me out at night, but when taken during the day, it really doesn't at all. At most I get a calm feeling, during the day, but not a sleepy one. I'm unsure if Valium being long-acting versus Ativan being intermediate-acting makes a difference in this.
Do you also take Seroquel (I assume IR) in the morning, or just at night? I take 600 mg of Seroquel XR at night. Until recently, I also took 50 mg Seroquel IR at night, but I've since been weaned off of the small IR portion. Neither made/make me tired during the daytime, but perhaps since I've grown used to them over a 12 year period. I remember that even Seroquel XR (all at night) made me drowsy into the day at the very beginning. It's been a very long time since I took Risperdal. I forget if it made me at all drowsy. I don't think so. I rather remember other side effects.