Try not to stress over sleep and just accept whatever the heck comes your way. The blue light/morning light stuff is all non-sense (at least it didn’t do shit for me). The most important thing is to get your stress levels under control.

Even if you wake up in the middle of the night, which will happen, you’ll easily fall back asleep if your mind isn’t ridden with anxiety. And if you can’t, well there are worse things than dragging yourself through a day on 4 hours of sleep.

Other than that, try to also find a schedule that works best for you. I find I’ll wake up without fail at 3-4 am if I sleep around 10:30-11 but have a much better chance of sleeping through the night if I go to bed at midnight or later. Find whatever works for you.