credit card theft

I recently found out that someone has been using my credit card number, as well as my name, and I don't know what to think about this. I feel horrible, and angry. It is someone in Florida and I have no clue how they got my number, I'm assuming over the internet since it is the card I use primarily for internet purchases. It makes me scared, I never thought it was really that easy to get someone's number, but obviously it is. We shred all our documents here so I don't think it was someone searching the trash. I have no idea. They even changed the address and phone number with the credit card number, and cancelled the old card, and got a new card in my name. This way, the card company would not be calling me or sending me bills that I would question. I am scared they have my SS # and they will try to do other things in my name. I have a fraud alert out on my name for 90 days but how do I protect myself from further damage? I feel so violated and angry. If anyone has any experience in this, let me know!

Things going well otherwise. I've been doing some exercise almost daily, and I am eating better. I am back in school Tues and Th nights, and so that keeps me busier and helps me eat less. I am feeling good about things, and hope to keep it that way.