Congratulation on your new pup Sam.
First of all, if someone grabbed you from your friends and family and stuck you in an unfamiliar place with completely foreign things and strangers you might be a little freaky too. Without being too critical, the point is that a new home is a HUGE change. Expecting a pup put through that experience to instantly be a "normal dog" may be unrealistic. Some might be fine. Others might be more unsettled.
The second thing to keep in mind is that puppies go through fear phases. It's natural. This might be one.
Agree with Tanza that it would be great if the breeder did a bang up job on the socialization front but that can take a lot of work and people don't want to pay for it. I'm not saying they didn't but socialization happens less often than we'd like. In this case there will be some extra work needed on your part.
In doing that, the treat suggestion is great. Once your pup has decided that you're OK, when people come over, or if you take her out, have strangers give her some treats. Works wonders. FYI treats don't have to be that special. Standard kibble usually works.