Headaches are very normal. It's same as going through any withdrawal. You're not eating so it's normal for your body to react this way. My first day ihad such a horrible headache at night i couldnt sleep but i also didnt take anything for it so i just suffered through , and it went away the next morning. Im on my 3rd day and i still have a slight headache but its normal. It usually goes away after 4th or 5th day. Don't Worry about not going through with it. I've failed numerious times in the past.