Exercise, ideally on fresh air, maybe walks every day... Sunshine too..
Eat something: food in general makes you feel better (of course in moderation) - you may have low blood sugar or lack some essential vitamins/minerals or such. Avoid sweets and sodas (sugar and phosphoric acid destroy the good minerals and vitamins). Some people even need to avoid sweet fruit and need more protein to stabilize blood sugar. (So white pasta can work for a bit, you may need something more to 'stabilize' it or the blood sugar will drop..)
Some people may have food sensitivities (gluten, milk..) and may need to avoid certain foods..
Also good for nerves: apples, oatmeal... some herbal teas like melissa or mint (though in moderation)
You may be lacking B vitamins or magnesium, good to check first, eg on Cronometer or fitday... (free programs where you can track your nutrition and see if there are any mineral/vitamin deficits) There's info on foods rich with these online too.. It's good to eat a balanced variety of foods..
Chocolate has magnesium and some other things too, so that can explain the cravings sometimes.. It may be better to go for dark chocolate or other sources of magnesium though... (like leafy greens etc) Hmm, I'm hungry, lol!