What's Crabby mean?

Last time I wrote I asked everyone to help me find out what a punk was, now I have a new problem.

Mum hasn't called me a punk for a few days, but she calls me crabby alot. I don't like it because it is very close to my name (Carbi, Crabby - say it out loud) and so I respond before I realise she is being mean and not calling me by my real name!

I've discovered that a Crab is:
A crustacean with a rounded thorax, a short abdomen tucked under its body, and, in most species, large front claws. www.reefed.edu.au/glossary/c.html. (Whatever that means!)

And I found this picture:
So that must be what crabby looks like - and once again I don't look like that!!!

PLEASE help me!!!

Carbi xx

PS Mum and Dad also call me Carburetor, which is a part in a car, and Carbohydrate, which is actually my full name and is also what Dad needs to eat when I tell him to!