I got sunburned yesterday and now i have a headache, my hands are shakey and my heart is beating fast even at rest. what is going on?

Mild heat stroke: you probbly suffered a mild heat stroke when you wear out in the sun . Stay cool , Hydrate , by drinking plenty of juices & fluids , NOT soda . rest . Take cool showers . Apply ALOE to your skin to ease thepain . use NSAID for pain . it should resolvein 24-36 hours . if not, go to urgent care .

Dehydration: You may be describing dehydration from environmental exposure, given headache, tremors & fast heart rate. Drink enough water to make your urine clear. If no better, go see your Family Doc or Urgent Care.