Mindfulness
Simple, secular, and scientifically validated exercise for your brain.
Some people think that practising mindfulness is all about meditating! WRONG! Mindfulness is calmly acknowledging and accepting your feelings, thoughts, and bodily sensations.
This might mean you have an easier time shrugging off worries, and that set back - from big assignments to everything happening in your personal life - don't hit you quite as hard.