Having a crush on someone is very similar to being addicted to drugs. The limbic brain, the same part that gets addicted to drugs is responsible for the feelings you have when you develop a crush. Our limbic brain hasn’t evolved since two million years ago; therefore, the kinds of things that we normally find attractive have not changed since then.
It’s tough, asking a person to get over a crush is like asking a heroin addict to quit. It really is not that easy. Once your limbic system is used to the regular level of dopamine coming in, it’s going to make you do things; whether you like it or not.