I can't eat or sleep at all. I'm feeling weak and dizzy.

Symptoms of sunstroke: Headache, muscle cramps, fatigue, dizziness, hot dry skin, flushed skin, high body temperature, lack of sweating, rapid pulse, rapid breathing, seizures, loss of consciousness.

Disorders like depression can also cause you to feel drained of energy, a symptom that can contribute to your grogginess.