That’s normal: Anki's not showing me all my cards! - Frequently Asked Questions
In your first screenshot, you can see that some cards are going to be due on September 27th and 28th. I don’t know your time zone, but I assume you’ve posted on the 26th, and some cards have appeared in the meantime.
If you want to cram before your exam, you can use a filtered deck: Filtered Decks - Anki Manual
Since there is no indication that anything is wrong with your scheduling, the error appears to be unrelated. Try using the Check Database function.