I've found Ashwagandha root extract (Sensoril) and
L-Theanine (Suntheanine) to have significantly helped me deal with stress. Just as important is to get ample sleep on a regular basis as sleep deprivation over extended periods of time can interfere with neurogenesis in the hippocampus, at which point learning becomes more difficult, mood regulation can suffer, and more, all of which can be quite stressful in an academic setting. A healthy diet and regular exercise, even just an hour of continuous walking, is also quite beneficial.