Love or Karma made me feel like this?

It's just an obsession that you can't get over. It's an addiction like everything else. People struggle with drug addictions for their entire lives. The key is learning to cope with it. You might never fully get over this obsession, but it will get easier in time. Just remind yourself that this person probably isn't even thinking of you. You're wasting your valuable time when you could be building a life for yourself, but instead you're obsessing over someone who is out living life. Wake up to reality and see that you're a worthwhile person, and you deserve to find love with someone who will love you back.