What should one do when feeling distressed, lacking self-confidence, and frustrated while studying, especially with a sense of guilt when taking a break?

What the questioner feels are whisperings from Satan. She should remember Allah's blessings upon her and her success, and she should frequently express gratitude to Allah and be content with what Allah has decreed. For "contentment is the heart's tranquility with Allah's eternal choice for the servant, that He chose what is best for them, so they are pleased with it." She also should not overexert herself, and she should organize her time between her religious, worldly, and academic duties.