Our environments to have an effect on us, and yes, it can be almost debilitating. When under duress, or stress, for example, our bodies enter even a mild fight-or-flight response. When this happens we secret adrenalin and our bodies secrete cortisol. These are the two chief 'stress hormones.'

Cortisol has benefits when in acute stress, but not when in intractable situations where the stress goes on for weeks and month. It begins to impose stresses on the body all by itself, including suppressing the immune system and encouraging inflammation and other comorbidities such as metabolic syndrome.
https://www.sciencedirect.com/science/article/abs/pii/S006524232400101X#:~:text=However%2C%20prolonged%20activation%20of%20this%20axis%20and%20increased,visceral%20obesity%2C%20both%20significant%20contributors%20to%20metabolic%20syndrome.
Untreated stress (meaning you're not fixing the trouble and it doesn't go away) can cause rumination at night when you're attempting to fall asleep. That friendship that fell apart so catastrophically last summer...it still plays on you mind, maybe because you're starting to be honest and realize you were largely the chief cause of it by inaction or action. It causes poor sleep, or less than you need because you lie awake for an hour instead of falling asleep inside of 10 minutes which most people in 'equilibrium' tend to do.

Physical exertion can cause inordinate physical exhaustion which has an effect on sleep. If you have sore muscles, blisters, joints, or just did too much, you might have trouble getting to sleep. You can be over-tired.

You may have a hormonal imbalance of some kind. An endocrinologist can help to pinpoint any defects or deficiencies, but also production of too much hormone in some cases. Thyroxin is an example.

Some, like me, have very active minds that can't get too much stimulation, or so they tell themselves. Then, come bedtime, they're still running at 100 MPH upstairs, figuring out a problem, or a design, just how they're going to resolve something.

I find that getting into my hot tub at 0100 hours is great! It's part of my bedtime routine, along with brushing my teeth, washing my face so my medical tape will stick to my mouth all night*, and putting in silicone ear plugs to keep street noise to a minimum. The tub is quiet time out in the dark back yard, a time to sing a hymn, say a prayer for someone, to find gratitude for something...it gets me out of my head.

*I have sleep apnea and wear a nasal mask. It only covers my nose, leaving my lips exposed. When I sleep, my lips lose their tone and relax. The machine has enough pressure going into my nose that my lips separate and the air, seeking the least path of resistance, issues from my mouth, thus awakening me repeatedly. Nobody can 'sleep' like that! So, I tear off a remnant of medical tape and place it over my mouth. Works like a charm.