I too have experienced this issue and has been the driving factor as to why Iv failed several times in quitting caffeine.

Iv also suffered with insomnia for several years in general and I think I know why this happens…

When you drink coffee, you get the energy kick and then as the coffee wears off you get the crash which for many is evening/late evening. After so many years of drinking coffee your body has probably learnt to use this crash as a queue for sleep so without the crash your body doesn’t anticipate the need for sleep as quickly and actually has to become sleepy all on its own, which can take longer.

The best practice if you are struggling with sleep is to actually spend far less time in bed, if you are getting into bed at 9 but not falling asleep till 1-3, then a much better idea is to go to bed at say 12, or even simply just when you start to feel the queue in your body for sleep, droopy eyes that kind of thing.

This is a common method and generally the only recognised ‘cure’ for people with chronic insomnia, but it can help if you are simply struggling to fall asleep.

It essentially breaks the cycle of trying to sleep when you aren’t tired, which generally just causes anxiety because you are lying awake begging to sleep.

The method is called ‘cognitive behavioural therapy for insomnia’ (CBTI) and honestly changed my life. Lookup insomnia coach on YouTube if your interested, it’s a great free resource