Right now i exercise 5 times a week and take 17 blocks of food daily. As i have exams starting at the end of June and lasting for two weeks, i expect not to be performing any exercise during that time.

As such, should i recalculate my zone blocks? Would it affect athletic performance when i resume exercise?

It's fine to cut back to your protein/block requirement calculated at a lower activity level if you wish. Doing so would not effect your performance when you resume exercise two weeks later, though the two weeks without any exercise may impact your ability to resume exactly where you left off, depending on what your exercise activities are.