Yeah this has happened to me before. When you're already lacking in self-esteem like Kasumi, it really hits you hard.
Happens a lot to me too, in more minor ways. Can't help but think that it was my fault, that I did something wrong, that I should have done better, that I can't keep up, that they don't like me, etc. Anything except putting the blame at someone else's feet, or even.... nobody's feet.
Her obsession with grades is also very reminiscent. I was never a good student, but I very much grounded my own worth as a person in how much output I could produce for a very long time. Still do to some extent, or in the very least it's hard not to think "I haven't done enough yet."