I am hoping you can clarify some questions and concerns, that I am sure other readers will also find useful, around baby milk formula and milk substitutes.
Are you chewing fingernails, taking long breaks in between study periods, eating more, exercising less, cramming more, and sleeping less? Sounds like exam stress to me. Normal life stress is compounded by exam stress and when unusual things happen just before exams, performance can plummet and parents become despondent at their petulant offspring. So what to do?