Ok first of all I would like to say thank you. Thank you for posting your thoughts and feelings, you might not think it but that takes courage.
After reading your post I just want to say that I'm here for you. There is nothing wrong with your head at all. Your mind is just over compensating for some of the things that you did not hav, and that is normal.
You say that "sometimes you think your parents are against you and that they do not love you" well my friend..nothing couldbe further from the truth
your parents just have a hard time understanding but I'm sure that once you tell them your full story they will give you the love and warmth that you most defiantly deserve. Is your brother older then you? Because if so it's only natural for younger siblings to look up to older ones within the family. If you are older then your brother that just shows that you are generous and kind hearted.
The main thing that has too stop is the hitting. Your body is very important. Are you focusing on any certain area. Hitting yourself is seen as self harm and there are many different things you can do to try to stop. One type of compensating for hitting yourself yould be to get an elastic band and whenever you feel like hitting yourself you slap the elastic band against your wrist. This is known as a stress reliever and is alot safer then injuring your body.
There is nothing wrong with your head. You are not alone, your family will always love you and we will always be here for you. Thank you for being brave and having the courage to post.