This quote is referring to jealousy, which is an unpleasant emotion or feeling that someone has when they are worried that someone they care about may be interested in or attracted to another person. This quote is saying that when you get jealous you get a splitting headache that causes a lot of pain, you can feel like you want to harm the person you are jealous of, and you might feel worthless and inferior to them. This is not a positive thing and is said sarcastically with a ‘Yippee’.