@FanOfMostEverything  
You were right. Because after yelling at her friends (mostly Pinkie) that she’s better off without them, she suddenly realized that she was possibly a fool or a jerk because she should have listen to Queen Novo. She screwed up her hope of saving Equestria because she thought the pearl was something to used to fight the Storm King and his troops along with his henchmen, Tempest Shadow and Grubber. She’s possibly the one responsible for making a decision that could go wrong, ruining everything by trying to take the pearl and distracting the Mane 5 and Queen Novo, failing the friendship between and herself, letting everypony including the Mane 5, Spike, the Princesses, her brother and niece, the CMC, Starlight, Trixie, Sunburst, Discord, and the rest of Equestria, Queen Novo, Princess Skystar, and the rest of the hippogrif/sea-pony population, and possibly Capper, Captain Celaeno and her crew down, and gives up all hope saving Equestria from the Storm King. That grieve let’s Twilight felt remorseful or guilty about her near-selfish actions to her friends in Seaquestria (even though Twilight would never be selfish), crying over for what she’s done to herself by not trusting her friends and thinks all her friends hate her, or betrayed her, or no longer her friends, (Even though some fans who possibly hate the movie or Twilight’s yelling at the Mane Five (mostly Pinkie) and misplaced blame on Twilight. Similar to how fans misplace blame on Hot Rod/Rodimus Prime after their remorse of Optimus Prime being murdererd by Megatron in the Transformers movie.) and says that there’s no hope to save Equestria from the Storm King at all this time anymore and it’s all her fault that Equestria is completely doomed. But ultimately, it was the Storm King who completely doomed Equestria along with his troops, and henchmen throughout the entire film conquering, destroying, and ruling the entire land/kingdom of Equestria and punishing, enslaving, arresting, and seizing, capturing, kidnapping, and menacing all the inhabitants across Equestria.

It was at this moment she knew she messed up.