After a while with LC everything that has added sugar tastes really sweet. Folks can even taste it in their salad dressing.

Some of my favourite LC snacks are nuts, peanut butter or cheese whiz on celery, slices of melon, cheese. If you can stay in ketosis, it will help with the hunger.

Since you are under stress right now, take care of yourself in other ways: listen to music, laugh with friends, take a walk, do yoga, read the funnies ...
but make sure you eat properly: that will help a lot especially if sugar gives you mood swings.

Get some healthy oils like flax oil, olive oil and oily fish. They will help your brain, help you study and write the exam, and perhaps help your mood too.