You can’t keep fighting to be with someone who isn’t fighting to be with you, you can’t keep holding onto someone who is not holding onto you, you can’t keep planning your future with someone who doesn’t plan theirs with you, you can’t keep running back to someone who is running away from you, you can’t keep loving and caring about someone who shows that they no longer love you, and you can’t keep taking someone as a priority yet they are taking you as their option. Trust me it’s a waste of time and energy. No matter how hard and hurting it is, you have to let go and open up a new chapter. You deserve to be happy, loved and cared for not to be sad all the time, to have sleepless nights, to cry and plead for someone’s love. Think about it..... 
Sounds like you've been hurt. Stay strong. Someone better will come along.