You might have set your biological clock(in your mind) to wake up @ thee PM bc every nite you concentrate on the fact that you’re gonna wake up at three PM. For example I wake up @ a different time each day, when I go to sleep and set my alarm (on mobile) on 7.50u, I concentrate on that time, and the next day I woke up 7.49u realizing I set my alarm 50 min too late. But I woke up bc I thought of that time before I went to sleep. So I set my I believe I could even go without an alarm but not when Im really tired. You should try and concentrate on the time you have to get up, for example look at the clock and say to yourself “I have to get up at 9 tomorrow. At 9, I definetly need to wake up/get up/be awake.” And repeat about 3 times! You’ll see that you’ll wake up at 9.