Haraam relationship

I am 15/16 years old. I have unfortunately fallen in love with my cousin. I don't know how it happened but it did. I tell myself that it's infatuation. I really don't know what to do. My thoughts are about him for more than 1/4 of the day. I hardly ever speak to him. Either way we don't generally communicate. We do if there's a need. I do unfortunately see him and there's no purda between us. I need help. I want to stop thinking about him. I am not in the position for marriage right now, I want to focus on my studies. I feel sad when I see him on social networks etc. and not following me back or liking other girls posts, tweets or pictures. etc. I hate myself so much for feeling like this. The thoughts come and I don't know what to do. Sometimes I literally bite my arm to stop my stupid mind. Please advise on what can I do? I am doing hifz and Aalimah. I can't believe how bad I've become.