J.S.
I think the trouble is that you are expecting something that isn't age appropriate for an 8 week old. At that age, their sleep and wake cycles are still extremely immature, and ANYTHING can alter them.
A professional day care with educated teachers and caregivers will understand this, so you don't need to worry about 'sleep training' your baby.
At this age, I wouldn't worry about setting her down while she naps. I used to carry mine around in a sling at that age; they took most of their naps ON me until about 6 months!
You can create a regular schedule of waking and napping (babies that age usually need to sleep three to four times during their waking hours) but don't expect her to GET it right away.
So say you'd like her to nap from 8-9:30 AM. Nurse her/bottle feed her a full feeding at 8 AM. Turn off the lights, shut the shades and rock her until she falls asleep. If she wakes up again, rinse and repeat, but don't turn on the lights/open the shades/turn on the radio until 930, when you actually WANT her to be awake. Just don't leave her to cry! At this age, they need to be parented even when they are sleeping.