Bad mother

I am a bad mother. I know this now because I finally admit to myself that I don't like my step son. I'm more mother to him then his own mother but that's beside the point. He's 6 so I would love for this feeling to go away the older he gets. He's one of those kids in school that acts up to get attention. He is always doing stupid stuff thinking it's funny and expects us to laugh at him. He acts as though the cute things his two year old sister does is still cute for him. He's loud and always talking like a baby and cried about every little thing. He's not like other little boys his age, playing with his toys in his room, instead he's always fighting with his sister to play with her toys, or just fussing with her about everything. He's always looking for attention and I get it, trust me I do, he's looking for the attention his own mother doesn't give him. I feel bad because it's my job to reinforce that he is loved. I'm just so tired of his annoying antics.