I weighed myself about 4 days ago and I weighed 220lbs. I weighed myself this morning and I weigh 182lbs. Did I take the dieting too far? I have been getting headaches every few days but my friend said it might just be because my body is adjusting to eating healthier, is that possible? I have been running 4 miles every day and doing a 45 minute yoga routine and eating half an apple for breakfast and 1 cup of pasta for lunch and soup or a grapefruit for dinner. This all seems practical and healthy but I don't know why I feel so bad. Am I pushing myself too much?

You wouldn't necessarily be getting headaches from eating healthier but headaches from
Withdrawing from not eating what you use to. Like if you gave up soda you could be having caffeine withdrawal, if you gave up chips and snacks and junk food you could be having withdrawals from the preservatives they put in them like message.
You could be getting hunger headaches as well because from that little bit of food you mentioned your body must be craving some vitamins, minerals and other nutrients.

Try eating a little more if that is all you are eating cause it sounds like you aren't getting enough protein and fiber and other essential nutrients maybe eat a piece of toast with the apple and have some eggs some mornings too. Eggs have a lot of nutrition like choline
ENC - Egg Nutrition Center

Then for dinner add some meat and a potato and vegetable.
A nutritional/alternative guy said that you should eat meat approximately the size of a deck of cards.

As for exercizing, especially if you aren't use to it try cutting back to no more than 20 minutes every other day. Your muscles need a day to relax or you are stressing them which can cause a headache too.

Are you getting headaches due to working out a lot/not eating enough? Absolutely.

Half an apple... a cup of pasta... soup OR a grapefruit for dinner. That roughly calculates to about... what... 500 calories?

Your body needs roughly 1800 - 2000 calories simply to FUNCTION... -2000
You're running 4 miles a day... give or take 100 calories per mile... -400
Not sure how much yoga takes up... but we'll just say... 45 minutes of yoga... -100

... so. You're in deficit of 2000 calories a day.. . may explain why you're having headaches.

Keep it up, you may end up with kidney failure and long term heart problems.

Exercising is great... but you need to gas in the car to make it run.

Instead of that half an apple, make it a whole apple for breakfast.
Instead of a cup of pasta... why not make it a salad with some grilled chicken?
For dinner, nothing wrong with some baked fish with steamed veggies.

There is a way you can get all your nutrients while losing weight/dieting.

Well first I don't believe it is even humanly possible to lose 38 pounds in 4 days, a body just can't lose that much weight if you don't eat anything.

But except for perhaps a short fast, the food you eat is not correct or healthy. In that you can destroy muscle and health eating so little.
What you want to do is a even weight lose, a proper diet and correct exercise