WElcome to HCM
We understand your concerns
Late night studies without enough sleep in itself is wrong. It will be wrongest if you do it with medicines like vyvanse
for long period continuously. Body has a rhythm which needs to be assisted and allowed to function properly. Over and above, such studying or working always produces negative results. You study upto 12 night and sleep. Get up at 6 and study again and you will be fresh and should get benefit. Your body clock warns you with several warning signs if the pattern is disturbed and your feet problem coule be one of those signals. Take full rest for two days ad it is over,
Good luck for your tests.