What should I do? My husband has taken my baby away from me?

The only advice I can give you is to get your own lawyer fast. Your husband must be serious about ending your marriage if he had you arrested. It's odd that he is trying to get full custody. It doesn't sound like you are an unfit mother, but just had one bad fight (Hey, I've been there and done that myself). He is probably just confused right now and feeling like he needs revenge for something. Things might get better. Give him some space, but do get a lawyer.