Rescue Remedy (a Bach Flower Essence available at health food type stores and even on Amazon) works very well for me when my insomnia is stress-related, with zero hangover the next day. You can also use it during the day for acute times of stress. The drops do have some alcohol in them, though. The pastilles might be alcohol-free.

I've also had success with Valerian capsules (no way can I imagine drinking that stinky stuff in a tea!) and no hangover from those, either.

Good luck with everything, take good care of yourself.

S