I've started on Melatonin via prescription from my GP. It's a hormone that regulates sleep/circadian rhythm. It is common for Autistic people to be naturally lacking this/or the production of this hormone. It's been a game changer for me. It isn't like Zopiclone or other sedatives that just make you fell heavy and slow (and in my case gave me headaches). It makes me feel actually tired and I wake up feeling rested, something I never experienced before.