Hydrocodon is Vicodin which my sister was prescribed with her son during pregnancy. Like previous poster said talk with your dr just so they are aware of what you are on. They may change it may not but they need to be aware. You can always just call and talk to the nurse about it at the office.
Sometimes women are prescribed pain medications during pregnancy because the benefits outweigh the risks. Being in severe pain may cause more problems to a baby then the pain medication you took. I would let your OB know about it. Congrats on your pregnancy!! Hope you are feeling better soon