Tanyah, this is a common concern. I worried about the same thing with DS1 early on too. But as a PP said, peace of mind is really important so if you are worried I would talk to your GP or MCHN. Otherwise, if you wait a couple of weeks, you'll probably start noticing reactions by 12 weeks or so.

FYI the hearing test in hossy makes sure that sound waves reach the brain, but it doesn't rule out all hearing problems.