This sounds like stress and anxiety driving the insomnia. It’s horrible, I’ve experienced it.
Yes, exhaustion will eventually kick in and you will get some sleep but in the meantime…
Cut down or cut out tea and coffee and caffeinated drinks (you may have a short- term reaction, but hang in there)
Get out into bright light in the morning and during the day, take some physical exercise if you’re able, but not late in the evening.
Remove yourself from contact with the stressful issue gradually through the evening eg if it’s work stress, don’t look at work emails.
Check out ‘ sleep hygiene ‘ tips and follow those.
Work on the stressful issue or the anxiety - confide in someone, ring a helpline, write down all your worries.
If I can’t sleep I listen to audiobooks. They distract my thoughts and I often drop off.. If I don’t feel sleepy at all and am stressed, I watch TV but something very gentle and slow like a gardening programme or an art program . And have the lighting very low and move around quietly. Essentially telling the brain that this isn’t daytime, it’s a quiet time. This nearly always works after an hour or two.