Help in changing habits

Anyone here has successfully changed any old habit. Need help. I am sleeping daily at 3am and then have to wake up at 7 due to some commitments. In the morning obviously the feeling is that I am not doing this again, but post 10pm, just not able to go to sleep, mainly spending time on gaming/social media/YouTube. And it is not like I am not sleepy, but just not able go to bed.