Sounds like you have body dysmorphia. Maybe see a therapist and adopt a healthy lifestyle of a proper diet and adequate exercise. Don't beat yourself up, please. You only live once.

Starving yourself is entirely the wrong way to do things here. Not only is it not sustainable, damaging to your health, and teaching your body to actively store all the fat it can, but it’s not going to fix the underlying issue of your body image. You’ll just be underweight and miserable if it works. Seek out a psychiatrist and, only if they decide that losing weight can be helpful in your specific case, a licenced dietician who can teach you how to lose weight responsibly and sustainably, *and* at what body weight you need to stop.

Don't worry; the main character is probably eating her grief and will be 300 pounds in the next version of the game. Just go to the therapist. Maybe there will be a "accept your body" game with the same Otome next year.