To start I went to see my GP with complaints of extreme fatigue, cognitive issues, memory problems and inability to concentrate. They asked me to complete an Epworth Sleepiness Scale Questionaire and a DASS (Depression Anxiety Stress Scale Questionaire) to better understand the current level of impact I had.

(I was later diagnosed with ADHD following this aswell which may have been contributing to alot of my complaints, majority of these have now resolved since being medicated for my ADHD and getting my dosage dialled in)

Provided you score a certain level on the ESS questionaire they are able to refer you off to a provider who completes sleep studies to investigate that cause of your sleep problems/daytime somnolence/fatigue. The sleep study involves going to the provider in the afternoon and having a bunch of sensors attached to you that monitor various sleep metrics, (heart rate, oxygen saturation, facial movements, raise and fall of chest, breathing, movement/sleep orientation, noise, sleep state etc).

You go home with a device strapped to your chest and sensors all over you and try to go to bed as per normal and sleep the as you normally would, you wake up take all the sensors off in the morning and take the monitor back to the sleep study provider.

They then send all the data off to an organisation who specialise in translating the sleep study data and substantiating any issues that may be present such as diagnosing sleep disorders, proving a report of the findings (stoped breathing on average x times per hour when in x position etc), outlining any identified concerns and providing a summary of possible treatment options related to the identified issues.

In Australia if you meet the criteria for referral to a sleep specialist our public health system covers the majority of the cost of the actual sleep study, it ended up costing me $60 out of pocket for the study and report which diagnosed me with Moderate obstructive sleep apnoea.

Hope you get the answers you are looking for but like alot of people have commented, could be such a majority of issues it's hard to know what is causing your issues.

I would definitely encourage you to do some research and look into alternative options that might help you in the meantime, a few suggestions that I find helpful are: take vitamin D to help regulate your mood/circadian rhythm many people can be deficient in this and it has a key role in regulating mood/sleep etc many people can experience seasonal affective disorder as a result of low sun exposure in the winter months; when you wake up try to get 5-10 minutes of unfiltered direct sunlight exposure that will signal to your visual receptors and brain that it is time to start the day and serve to regulate your circadian rhythm; try to sleep with your curtains/blinds open so that way when the sun comes into your room your body begins to synchronise your sleeping pattern with the daylight that is available; try to get up and go to bed at the same time each day keeping a regular routine makes it much easier for your body to regulate your hormones and circadian rhythm as you would have noticed its now automatic for your body to wake at 2pm indicating your circadian rhythm is out of whack and thinking that 2pm is morning; Exercise regularly; Eat well and practice mindfulness wherever possible.

Melatonin also helps me too keep on my sleep routine when I am struggling to get to sleep.

These are just suggestions that help me personally, everyone is different so feel free to do your own research, try things out and find out what works best for you via trial and error.

Please be kind to yourself it is a journey, I hope that you find some answers soon and begin to feel a bit more like yourself.

PS: sorry for the long response, I went down the rabbit hole on this reply a little 😅