There's some good advice here, but it really should be applied to older babies. 7 weeks is still a newborn, other than correcting day and night confusion, there's little you can and should do. At this age they eat and sleep on demand, and that's just kind of what it is. By 4 months, it changes drastically and is a good time to start sleep and nap training. But right now, it's not uncommon for a baby to struggle with being set down. If it's impossible for you to hold her during her naps, since you are rocking her to sleep, try moving her to a swing. She may wake up briefly, but hopefully the rocking motion and cradled feeling of the swing will put her back to sleep. You can also try wearing her in a carrier, and she will likely sleep that way.