I didnt quite get it when Edward said to Bella in the fist movie.."It's not like drinking ur blood for instance"

If I understand you correctly Edward means that drinking animal blood is not the same or as good as drinking a human's blood, namely Bellas. He's comparing it to how it would be for humans eating tofu. It's food and it sustains you but it's not the same as eating something else more appealing. So while Edward drinks animal blood he would much rather drink human blood especially Bellas.