How do you think Scrooge feels listening to Mrs. Crachit's words after her husband's toast?

We are not told exactly, but based on his his reaction just previous to that moment, we can assume he felt pretty terribly.

Just prior to the toast, Scrooge had been asking the spirit about Tiny Tim. He saw that he was crippled and asked if the little boy would live. The ghost retorts back to him,

“'If these shadows remain unaltered by the Future, none other of my race,” returned the Ghost, “will find...

We are not told exactly, but based on his his reaction just previous to that moment, we can assume he felt pretty terribly.

Just prior to the toast, Scrooge had been asking the spirit about Tiny Tim. He saw that he was crippled and asked if the little boy would live. The ghost retorts back to him,

“'If these shadows remain unaltered by the Future, none other of my race,” returned the Ghost, “will find him here. What then? If he be like to die, he had better do it, and decrease the surplus population.'”

Scrooge hung his head to hear his own words quoted by the Spirit, and was overcome with penitence and grief "(Stave Three).

He feels ashamed at his previous remarks and when the ghost throws them back at him, he has no response. Directly after this is when Bob Cratchit makes the toast to Mr. Scrooge as the "Founder of the Feast," and Mrs. Cratchit says,

“It should be Christmas Day, I am sure,” said she, “on which one drinks the health of such an odious, stingy, hard, unfeeling man as Mr. Scrooge. You know he is, Robert! Nobody knows it better than you do, poor fellow" (Stave Three)!

Although we are not told how Scrooge reacts here, we are told that the mood of the entire family dampens after her comment. It is clear that she has reminded them of something very uncomfortable, Mr. Scrooge's stinginess. They do recover from this brief melancholy, but it is obvious that in so many ways Ebenezer Scrooge has made it clear to people that he does not care about them. That is why we see the spirit throw his own words back at him and why we see Mrs. Cratchit respond with such anger. So, we can assume that Scrooge is feeling pretty bad about himself and how others perceive him as a result of the way he has treated them.