It means that whatever happened to your levels during the night, your liver has decided that around 7 is where it likes you to be, possibly because this is where you have been for a while and your liver is used to these levels.
You may have had rises or falls during the night, but your liver has put you back to 7.
Hopefully, once your bedtime level comes down, your fasting level will follow suit, although this doesn't always happen, and rarely does it quickly. Our fasting levels are often the highest of the day, and our pre-evening meal levels the lowest of the day.