I am really struggling to sleep and I want help please

I'll try to keep this as brief as possible but there is a lot to explain to maybe help explain my situation.

I guess I'll start with the fact that I am both autistic and have ADHD-C (combined typed). So sleep has been something hard to come by all my life but as of the last couple of months, sleep has been extremely poor, like to the point of spending 36 hours awake once or twice a week in this period. My body is lethargic and unwilling to do anything but my brain is running erratically and speedily. So there's a complete disconnect and unfortunately the brain keeps winning those battles. I'm on 40mg of Lisdexamfetamine and that works for around 5 hours but it doesn't help with sleep at all.

That aside, I am in recovery for opioid addiction/dependency (I don't know which label fits tbh) and I used to take as many codeine tablets as I could before entering a reduction plan as to where I'd take enough that I am physically unable to grab more and pass out, like it was that bad at points. So now I'm on significantly less than I was, the thing I used before to "self medicate" for not sleeping or escaping bad thoughts is something I really don't want to turn back to but it was the only time I could go to sleep whenever I wanted or simply escape whenever I wanted. I won't lie, the sleep deprivation is making recovery extremely hard because I feel like I'm genuinely losing my sanity and I've spent so many late nights where I should've been sleeping just crying because I can't sleep.

Then there's the third thing which is severe anxiety, there has been and will continue to be a lot of changes in my life and due to my drug problems & mental health problems, it means social interactions with professionals on a regular basis which stirs up more anxiety and so I waste my nights thinking up the worst possible scenarios and whatnot.

I was wondering if there's some kind of help available because ultimately I am fearful of going to my GP and being rejected for drug seeking or potentially being given medication which offsets another addiction, but ultimately I just want to sleep! Its almost 5am and I've been awake 32 hours. Its a constant recurring nightmare and its making my mental health significantly worse and making drug recovery ever harder each passing day. I've tried all the things they say online to do and what professionals have offered in advice but my brain refuses to ever shut up.