At first, Draco might be in shock. He didn't expect Harry to break up with him at such a crucial time. Then he could try to reason with Harry, begging him to stay for the sake of their unborn child. When Harry refuses, Draco could turn to his own family for support and close himself off from the outside world for a while.
Draco might become withdrawn. He could isolate himself from his friends and spend more time alone in the Slytherin common room, brooding over what Harry has done to him.
She might be heartbroken at first. Hermione is someone who invests deeply in her relationships. She would likely retreat into her studies as a way to cope, burying herself in books to try and forget the pain.
He could also react with suspicion. Draco might think that Harry has some ulterior motive, especially if the confession is of a more positive nature like friendship or love. He would question Harry's sincerity and might even test him in some way.
Harry could initially be angry and struggle. He's a brave character, and being tied up against his will would surely make him fight back. He might yell at Draco, demanding to be released and threatening consequences.
There could also be a chance for reconciliation in the future. Maybe they both realize that they made mistakes during the break - up. Draco could change his ways a bit more and Harry could be more understanding. Fanfiction often has these kinds of arcs where characters get a second chance at their relationship after some growth and learning.
Draco would probably be extremely angry. He might feel a deep sense of hurt and betrayal, especially if he considered Harry a friend or at least an acquaintance he could trust. He could start plotting revenge against Harry, using his own cunning and Slytherin skills to make Harry's life difficult at Hogwarts.
Harry might initially be very angry and hurt. He could cut off all communication with Draco and become withdrawn. In some fanfics, he would even start to avoid places where he might run into Draco.
Harry might be initially shocked. He's used to seeing Draco as this tough, arrogant Slytherin. But then, he could feel a bit of pity. He might approach Draco tentatively and ask what's wrong. Harry has a good heart, and despite their past differences, he wouldn't just leave Draco crying. He may even offer some words of comfort or a handkerchief if he has one.
Harry might be initially angry. After all, he's been hurt. But he could also be a bit confused, especially if he thought Draco didn't mean to do it. In some cases, he might just walk away to cool off and think about what happened.
Harry might be confused at first. He doesn't understand why Draco would think he's a doll fan. So he might just shrug it off and not pay much attention, thinking Draco is just being his usual difficult self.