So I'm confused--are you taking some kind of homeopathic valerian then? Or just valerian root in a tincture or capsule form? Valerian is safe during pregnancy; not sure about melatonin.
You might want to consider Skullcap tincture or tea. It's completely safe during pregnancy, and is fabulous for insomnia.
mama to DD 8/06, DS 9/09 Set the gearshift for the high gear of your soul