book by book, one at a time first *control!*
Ah Girl, stay calm. Emotional control is important for long term success. Make a plan, be disciplined and stick to it, flexible to adapt ...
Give yourself time, 15 mins breaks in between, to clear your mind, have a cup of coffee or tea, some light foods, be disciplined to go back.
I am of course, assuming this is about school related assignments, tests and exams.
but thanks anyway