Hello and greetings!
Your issue sounds eerily similar to Harley’s who posted here a few weeks back. Basically he used to go to bed at 10pm, would sleep until midnight then awaken and couldn’t go back to sleep again until 3am. After that, he would sleep until 6am when his alarm would go off and he would snooze it all the way until 8am, when he would get out of bed. Basically he had been sleeping like that for 3-4 years and accepted it as a way of life and almost gave up hope. The solution, which he found here, is actually going to bed later… Then when he tries going to bed at midnight, he actually starts sleeping literally all the way to 8am. Now he seems really happy with his current sleeping pattern because he says he used to struggle between choosing DIY work at home or watching his favorite tv series at night and now he could do both and still sleep great!
The lesson here is only going to bed when you’ve built a strong sleep drive and not what time it is. Your sleep drive builds up the longer you stay awake and for normal people, that’s 16-18 hours of awake time to generate 6-8 hours of sleep. So the question is how long have you been awake before you go to bed? Is it long enough? Experiment with 16,17,18 hours and find the magic number that works for you because everyone is a bit different. No matter how much you slept, always get out of bed at the same time each day. Do not compensate for lost sleep by going to bed earlier, taking naps during the day or sleeping in! Practise this consistently for at least a few weeks and you should see an improvement. Then when that happens, you can start extending your time in bed by going to bed earlier but always keep your out of bed time the same. Go in 15 minutes increments until you reach your targeted hours of
sleep. Bear in mind you might actually need less sleep than you think so be mindful of this when making adjustments. Also you should expect a bad night occasionally as your body adjusts to your new sleeping pattern. But as long as you stick to the plan, you should expect to see long term improvement in your sleep. Good luck!