That a chemical is natural doesn’t mean it’s non-toxic. Some of the most toxic toxins known to man (botulinum, ricin) are perfectly natural, yet deadly in extremely small quantities.
I don’t know about using aromatherapy in a room though. You should never put pure essential oils on your skin or the skin of animals (although some recommend it to deter ticks: adverse reactions are not uncommon).
I’m sorry you have night terrors. Have you seen a doctor about this? Sometimes it’s about REM sleep being predominant so it keeps you from entering deep (stage 4) sleep, so you wake up without feeling refreshed. This may be due to a chemical imbalance in the brain, such as too little serotonin present. There are OTC remedies like melatonin. It’s legal in my country but you should check how it is in your country and state. I recently did a MOOC on this subject, Neurobiology of Sleep, uni of Michigan. Sleep is SO important for our well-being! Much more so than anyone would’ve thought.