In general, you don't need to wake your baby for a feed. He'll let you know when he's hungry - unless he's poorly. The nappy changing is a different matter. It's quite OK to change a sleeping baby, otherwise they can get nappy rash, which can be very unpleasant for a little one.
Use your natural feelings as a mum. Only you know your baby, but talking to your health visitor will put your mind at rest, whether they have children of their own or not. A trained HV will have come across all sorts of problems like this, and be able advise what's best for you and your little one.
Finally Velvetee, although I hope that things turn out well for you, your reply was extremely rude to someone who was offering advice. The advice wasn't wrong, although new mums DO have access to a hospital/midwife helpline 24/7. I sincerely hope that your language isn't in every-day use.