When someone is in the attraction phase of love, high levels of dopamine and norepinephrine are released. Dopamine is known as one of the happiness hormones, and these chemicals can make people feel giddy and even euphoric. This reaction can also lead to decreased appetite and insomnia, which means you can actually be so “in love” that you can't eat or sleep well. Credit: Zareen Syed, theactivetimes.com