I used to love staying up late, working late, sleeping in. Getting up early is about getting on a schedule. A few years ago my cat started waking me up at 4am

I used to love staying up late, working late, sleeping in. Getting up early is about getting on a schedule. A few years ago my cat started waking me up at 4am, like exactly at 4 am +/- a few minutes. He would even keep on schedule when the time changed. So I started staying up, starting work at 4am. After a while you just get in a routine and you function normally. I would go to bed by 9 or 10pm and usually by Thursday/Friday I would be more tired than usual if I didn't go to bed early enough. I also gave up soda around the same time and switched to green tea and the carbonated unsweetened drinks. Getting away from soda I felt better had more energy. Recently we've been staying up late with friends and watching movies and I'm slipping back to staying up late/needing to sleep in so it's definitely about getting adjusted to a schedule and keeping on it. A 9am start isn't bad so you could probably still stay up later on the weekends and still adjust back. But I seem to feel better sticking to the same schedule all the time.