Stay overnight

Good evening.
The tests will start in a week.
I can not afford to spend useless time.
However, I spent useless time yesterday.
Yesterday, I had a club activity.
After it was over, I intended only to go to eat supper with my friends.
However, I went to my friend's house and stayed with him.
We talked about various things for a long time.
When I noticed, it was morning.
I didn't study.
I have no time.
Bye.