How large are the hoodies from American Apparel?

I really want an oversized, baggy hoodie, and I ordered a large grey hoodie from American Apparel yesterday. I thought this would be just baggy and cosy enough but having read that American Apparel sizing runs really large, I'm not sure whether to cancel my order and change it to a medium instead. I'm around a size 10 and about 5'6/5'7.