I'm worried because my hair suddenly started falling out rapidly.

Hello. I originally have a lot of hair, so I never had any concerns about hair loss. However, suddenly my hair is falling out rapidly, and I'm worried. After washing my hair once, I notice a lot of hair falling out, and my family is surprised. I have been busy and had no appetite for the past six months, eating roughly and casually, so maybe that's why? Certainly, when I tie my hair up, I can clearly see that my hair volume has decreased compared to before.