Do my worries during exams indicate weakness in my faith, even though I take the necessary measures and seek Allah's help? Does performing Qiyam al-Layl during exams indicate hypocrisy on my part? Does my complaining about excess weight indicate dissatisfaction with what Allah has given me?

The servant's turning to God in times of hardship does not indicate hypocrisy. Rather, one who abandons this is blameworthy. It is disliked for a person to cease acts of worship after becoming accustomed to them, as in the hadith: "O Abdullah, do not be like so-and-so; he used to perform Qiyam al-Layl (night prayers) but then abandoned Qiyam al-Layl." The most beloved deeds to Allah are those that are continuous, even if they are few. One who abandons Qiyam al-Layl is not described as a hypocrite. As for complaining about weight gain, it contradicts contentment (rida), but contentment does not negate taking legitimate means to address it.