Not all rest is equally refreshing. If you have a sleep deficit build up, a bad mattress, a loud environment, some psychological or physical condition, it can negatively affect your sleep.

You should look out for stuff that makes you sleep worse. I don't do sports in the evening, I try not to eat too late and I don't look at my phone the second I hit the sheets. There is also a midnight high I particularly struggle with. If I don't got bed before it, I absolutely cannot sleep, unless I take melatonin.

Takes a while to figure out everything for you personally.