Dean is a muggleborn and so adamantly denies the evidence in front of him. The war is just over so people must be looking for a laugh right? He can't be pregnant and if he was an omega then surely he would have been told years earlier. Surely he would have been warned that magical men could get pregnant and that he was one of them. It disgusts him to think they never said. He shuts out Seamus and refuses to go to appointments because frankly if they will hide that they will hide anything and he's never felt so alone.