Accept and embrace the fact that the person you're wholeheartedly in love with may not always love you back. This is how things work and are supposed to be. You may love a person, but they might not even have an idea that you exist.
And yes, that shit hurts. It hurts so bad that you go back to square one, trying to figure out where it all went wrong. But darl, it wasn't your fault. Sometimes, some things are meant to be.
You never know what's the future holds in store for you ;)