Your other respondents have listed excellent ideas and brilliant insights. I breastfed 3 babies for a total of 5 years while working 12 hour shifts in an emergency room, I have nothing to add to the suggestions that you've already received. "Ya do what ya gotta do."
BUT, you must allow yourself to relax and not be so worried. Worry/stress reduces milk supply. Babies pick up on the stress around them, especially in their moms.
You're probably worried about all of these things because you are leaving the baby. We moms are built with a genetic protective component that makes it extremely difficult for us to leave our babies - especially for a whole week.
As the child gets older, it doesn't get any easier, either. The focus of the fear changes. When we leave them and they're babies, we're afraid of everything from diaper rashes to SIDS in our absence. We never completely trust our caregivers, not even our husbands/the babies' fathers to provide the care and the sensitivity as we would.
When we leave our babies and they're 21 years old, we're afraid of all sorts of other terrors. It's a mom's job - to sense the dangers and prevent them.
You can't allow yourself to be controlled by your fears, though. Learn to find the feelings in your gut - the difference between real danger and over-protection. Being overly-protective or controlling can dominate you (ruin your trip next week), destroy your family, and, can ultimately be disabling to the child.
Good luck and let us know how it went when you return!!