I am numb most of the time and dont feel love?

Ever since I can remember I have always felt like my family didn't love me and I was a mistake, I have always found it very easy to lie about my feelings and only recently told them which they all dismissed and said that I am loved. I don't think I have ever actually felt love though. For someone or off someone.
I am in a relationship with someone I care about. But I don't think it is love. I don't want to hurt him but I don't think I do love him. With most of my friends I do care about them but I don't seem to be able to emphasise with them. I can understand why someone behaves how they do but I can't seem to feel sorry for them.
I feel numb most of the time. I get in very low moods some nights and sleep a lot, I can be very easily excited at some points and energetic and can be happy and I can get angry very easily.
I don't know if it is normal to feel this way - I feel like i just cannot feel love ever to anybody. I don't think I have a conscience as I don't feel guilty - it is normally what other people will think of me and getting in trouble which stops me. Is this normal?