Dear Tarl,
Hello from another person with fucked up sleep. Staying asleep is my old enemy since age 37, believe it or not. I have a set of recommendations that have worked for me, but only if I am disciplined. I'm giving this to you because I truly hate to see a pirate sink. This is 100% earnest. It is an overhaul project, and you can't half-ass it.
1) Goodbye to daily substances. Sedatives and alcohol by and large are the enemy of restorative sleep, especially alcohol and benzodiazepines. They suppress REM sleep, which in turn wrecks your memory and greatly increases the chances of dementia in the coming decades. If, as I once did, you have alcohol use disorder, you know it's not any fucking fun anymore, so get rid of the bad habit.
2) Find your circadian rhythm. Start with full-spectrum light upon awakening and dimmer light in the evening, because humans also respond profoundly to light. Even if you feel like hell, get up and get out in the garden right away. Take off the shades and let the morning sunlight shine into your eyes. Stay out there and start double-digging, turn the compost, haul away old vines, just keep moving for most of an hour, outside, before locking into the phone or computer. At least take a brisk 20-minute walk, rain or shine. Your circadian rhythm requires the right ocular spectrum inputs at the right time. Buying a light box to use while at your desk is good for those days when you simply can not escape morning laptop time. After sundown, wear blue-blocker shades without fail, and minimize screen time.
3) Exercise. As mentioned above. If you don't tire yourself out pleasantly during the day, your mind won't settle at night.
4) Sleep hygiene. Your bedroom should be restful and free of distractions. No computer, phone, or TV. Wind down reading an escapist book in the hour or two before bed. Then go to bed. If you get up in the night to pee, DO NOT CHECK YOUR PHONE. The world will be OK without your checking in. FOMO is a good habit to lose. Just go back to bed.
5) Racing, ruminating thoughts. These are killers. How to circumvent them? Distraction! Play soothing music. Or (and this is an exception for using your phone) play ASMR or a favorite audio book that you already know. It should interest you enough to keep you from ruminating but not so much that you stay awake to listen. Distract yourself from your troubles.
5) Stay well clear of Sam. It doesn't matter if you love her or if she's had a shitty life. Not your problem and she's already fucked your life up. Succubi have a way of doing that. Not worth it. Bitch should have BIOHAZARD and nuclear trefoils stamped all over her.
That's about all. Good luck, and peace out.
