<p>So I crammed multivariable calculus in 3 weeks and was getting high 90s/100s on MIT/Cornell prelims & exams. </p>
<p>Then I got a headache that lasted 2 whole days and I seem to have forgotten EVERYTHING.</p>
<p>And now that I'm trying to relearn the material it feels like I already know it but for some reason can barely do the problems.</p>