Can't Sleep, things going to shit and I don't know what to do

Sorry for being dramatic, but I feel absolutely awful right now and things seem to be moving in the wrong direction, I genuinely don't know what to do next.

So please forgive a long rambly message to people who struggle with just that! I got ChatGPT to make a TL;DR, which I found quite amusing:

• The poster is a 27-year-old who was diagnosed with ADHD this year and has been taking medication for the past 6 months, with a stable dosage for 3 months without issue, and generally positive outcomes.
• Following that, they have experienced disrupted sleep patterns for the last 3 months, finding it difficult to fall asleep before 3AM even when going to bed at 1AM, which is negatively impacting their routine and work schedule.
• Despite struggling with sleep and consistently waking up late, they manage to maintain productivity at work, which they value greatly. However, this is leading to further sleep deprivation, exacerbating the problem.
• This disrupted sleep pattern is making them feel constantly tired, disorganized, and slow but they still seem to function effectively during the day.
• Their work-life balance is skewed as their hours are shifted back, finishing work later, and they continue to be active until late at night, often forgoing relaxation time for themselves to deal with personal admin, projects, and other work.
• They have devised a new strategy to cope with the situation:
• They acknowledge that their biggest challenge will be stopping activities by 12PM, given their heightened productivity levels at that time.
• Despite the plans to manage their situation, they are feeling increasingly stressed out and overwhelmed, fearing the consequences on their health and personal relationships.
• They are seeking advice from the ADHD community that goes beyond typical sleep hygiene tips.

I'm 27, diagnosed this year, on meds for ADHD for around 6 months. All was going well, and was stable on my current dose for 3+ months before this became an issue.

I take 20mg dexamphetamine at 7AM when I wake, then take 70mg of lisdexamfetamine dimesylate at the same time or a bit later. I've tried halving the 70mg for a week or so, but no change. (on sleep)

Over the last 3 months, my sleep pattern has completely gone to shit. I've always been a night owl, and naturally gravitate to a 3AM-9AM sleep pattern when I don't have to be up. But I've worked a full time job for years, which means me waking up at 7AM. So I will usually go to bed at 1-ish, sometimes later. This has always worked quite well.

However, recently I've found it hard to get any sleep before 3AM. Usually, one I'm actually in bed, I've always fallen asleep quickly. My job is fairly physical, so I'm usually at least physically tired. But even when I'm going to bed at like 1AM, I'm literally just lying there unable to sleep. It feels unnatural, like trying to sleep at noon. I have energy, thoughts, and a nice sense of calm and quiet. It's gotten to a point where I haven't had more than 4 hours of sleep in the last couple of months more than a handful of times, and in the last two weeks, on two occasions I've simply opted to stay awake, because it's 0430, it's basically daylight (I bloody hate Summer), the birds have been at it for hours.

Maybe the worst thing is that I can generally get by okay. Morning is hell, always has been, but after about an hour I'm feeling the same as almost any day. I've been struggling to wake up, and have gotten progressively later at work over the last 12 months, where I'm now showing up 30-60mins late as standard. Nobody really cares, I have always worked lots of overtime, so I don't take lunch and work an hour or so later until my work is done. But my work is both important to me, and important to my colleagues. As much as walking away from it for a while may be a good idea, I'd be leaving everyone in the shit. It's a small business, if they had enough redundancy for nobody to be essential, none of us would have jobs!

When I get less than 5 hours, I notice it, but I don't think anyone else does. I feel slow, disorganised and very typically 'ADHD'. But I'm very functional. I'll do a full day, do overtime, come home, work on some other things, get caught up on the bare minimum, look at the clock, and see that its 1AM, and I haven't even done any 'relaxing' stuff for me yet, so that is, of course, the right time to playa few rounds of intense competitive games....

Even 420 doesn't seem to be able to calm me down enough to help.

I'm writing this after getting less than an hour's sleep again.

I've come up with some ideas on how to proceed, I'm just worried that it's the same kind of approach I always take that rarely works, basically schedule everything, ignoring the fact that the schedule will feel miserable, unnatural and that I can ignore it. I've tried to make this a bit more human. Current planned changes:

• Must finish work by 6PM, unless we are truly in crisis mode
• I will not eat anything after 11:30PM
• At 12PM I will have a shower, which I hope will prepare me for bed
• No computer after 12 (sorry me)
• Reducing morning lisdexamfetamine to 35mg. I don't think it's the medication, but it can't help!

The hardest bit for me is going to be stopping at 12. I have lots to fit in, and not a lot of time, plus I feel really awake and productive at 12. So just walking away from whatever I'm in the middle of is going to be hardest, when I know I could just not. I may shift all of this forward an hour for the first week, otherwise it may simply be too much at once. I'm hoping that, by resting better, I won't have things I still need to do by 12.

But mostly, I just feel like shit. I hate being late every day, I hate days like today where I don't even know what to do, should I go in to work? How to I make sure everything will be okay without me on such short notice? I know this is awful for my health, I feel very 'thin', and my heartbeat is so much more noticeable when I'm on no/little sleep. My BP was fine when I checked after a month of this. To be honest, I almost don't want to check again, because it will be high, and I don't know what I'd do with that, I already know I need to fix this.

Everything just feels like a chore at the moment, every nice plan with my gf is just stressing me out more, because all I see is even less time, more shit building up, and I don't even know how to prepare for a holiday when I'm living like this.

I've never really engaged with the ADHD community, even after my diagnosis, which is pretty dumb. I'm sorry to just dump all this at you, but I really need advice from people who realise that just repeating the same cliches about 'sleep hygiene' may not actually be helpful in this case.