I think I'm in love with someone I shouldn't be ='[ HELP!

Me and my nephew who is 10 months older then me, think we are in love. His stepmom doesn’t like me so last May she stopped us from seeing eachother, in June 08 we found out we had major feelings for eachother. Before we even knew, I rubbed him off quite a few times. We have been dating and last Saturday I rode my bike to see him, his dad found out but told me to just go there. I slept over there, we messed around and we almost kissed. I wasn’t afraid of my first kiss but the first kiss with him I am. I am constantly thinking about him, I cry if I don’t talk to him. Yesterday I had to go get my bike at his house and then he was a jerk, he hasn’t been talking to me since Monday. He is a piscies, I am a capricorn. Every day I cry about it, I talked to my counselor about it and she said she doesn’t think it’s abormal for me since my aunt almost married her uncle and they are still in love, 20 years later. I haven’t told my family, I am too afraid to. I told about 5 people, some from school some not. I don’t know what to do I think I’m getting too close to him and I think I am honestly truely in love with him. What should I do. I want to spend my entire life with him and he always tells me the same. How do I know if he means it. His mood flectuates so much I may talk to him one day, his phone dies and the next day he won’t talk. He didn’t want to sleep over my house this weekend so all weekend I was depressed and crying. He wanted to be with his friend instead and it felt like someone ripped my heart out. I have been not being able to breathe when I think about him, I’m going to the doctor tommarrow to see if it’s stress, physical like asthema or something, or if it’s truely because I am in love and it breaks my heart going one day without seeing him. When we were youger we hung out all the time, we are whicked close. His dad took him away for 6 years, and then I found him on the internet and his dad let us see eachother for about 5 months and then started being a jerk. Please give me some adivce, I NEED to know what anyone thinks, any advice I need to figure things out. All I ever want to do is sleep and cry about missing him and wanting to be with him forever but worrying what the family would do. How maybe could I go about telling my mom. She always lets us sleep in my bed, she doesn’t think we would ever do anything I always say never would happen just so I can be with him. I like sleeping in the bed with him. I’m 13, I don’t think it’s hormones but I just like being near him…I would go without EVERYTHING just to be with him.