Hair loss

Is it normal to have a huge amount of hair loss after having a baby? I’m 4 months pp and I have noticed I developed a small bald spot on my hairline and whenever i brush or wash my hair it falls out in chunks. Could this also be caused because of me not eating enough? I eat about once or twice a day and I am breastfeeding. I’m really worried because my hair is the only thing I like about myself.