It might look odd at first, but that's how rabbits look, at least if you try for more realistic style instead of TV-show one where they all look like hares xD
But nice job at first try. Rabits are not that easy to draw.

Oh, yes, the head...It gave me a headache.., I tried the arch thing you said, but it just looked...odd.So I let it be like I first sketched it (like this).Thanks anyway!

As I said before, you've got a good start, but I've got some constructive criticism for you: A rabbit's head isn't really concave. He should have a nice outward arch to his face the same way your drawing of Bigwig did. His head also appears to be a tad too long - it looks kinda like you're used to drawing something else, and you might be having trouble transitioning? Rabbits aren't quite easy to draw anyway at that. However, your ears look very nice(I always struggle with those dang things), as does the eye placement. The neck might be a bit too... long and thick, I think, but I'm not quite sure on that one. It's still a very good start, I think.