New baby rat

Question
We got a new rat the day before yesterday. He is a male, don'tknow how young (got him from a pet store), but is very small, so I guess about 6-7 weeks old. He was as active as I would have expected the first two days, but today he is very quiet. When we hold him, he burrows in our hair or clothing, when we set him in his cage he just sits there. He doesn't seem to be ill, not wheezing, sneezing or problems that way. Could he just be scared of his new home? Could we be handling him too much? Want to make sure we take care of the new family member.

Answer
First, congratulations on your new family member!!  If you've never had rats before, you will find them to be as fun and playful and curious and smart as a puppy, just in a miniature version.  Your experience is sure to be rewarding, as mine is.

I am however concerned that you only bought one rat.  You may not know that rats are very social creatures and it is almost imperative they be kept with one or more other rats.  Nighttime is the most active time for rats, realize that this is the time you are sleeping.  
They are sure to get lonely without a mate.  Also, even when you are there, you are busy much of the time I'm sure and your rat will often be alone.  They are not like hamsters or gerbils that can do ok by themselves.  Please consider a second one...maintenance and care for two is not much more than for one.  I strongly believe that this is the MAIN reason for his skittish-ness and fear.  Remember, he's been kept at the pet store with plenty of his buddies or brothers and suddenly, he feels all alone.  Now he has no one of his kind to play with and is fearful of you who are much larger than he is.  Believe it or not, a companion will actually help to "tame" your boy and make him more social and not as skittish with you...this is a proven fact.  

I can't imagine the pet store charged more than $25 or so for him, so I hope for his sake that you can get him a buddy soon.  Also, I never recommend getting a rat from a pet store for several reasons, one of which is that pet store employees generally do not handle them as they should.  A good breeder will handle babies from the very day they are born, and several times a day until they are adopted to assure that they are not afraid of humans.  I myself witnessed in horror a local pet store employee lift a baby rat by it's tail to let me hold him!  The other thing about pet store rats is that they are bred in rat farms with no attention to breeding out health issues. So I highly recommend locating a good vet that is experienced with rats now, so that if you ever need to rush your rats to a vet, and you don't want to be scrambling at the last minute to find one.  Often with rats, signs of illness mean they need immediate attention or it might be too late.  Trust me on this...with rats, you should never wait.  They can take a downturn very quickly.

All that said, I will provide you with information about "trust training" your new buddy. This will take a good amount of patience and time on your part.  Take things slowly, and work at his pace.  I'm attaching a link to a website about trust training a pet rat.  You can also find plenty more written on trust training rats on the internet if you are interested in more ideas.  
Here's the link -->  http://ratguide.com/care/behavior/training_playtime.php

If you do everything you can to patiently work with your rat, I am confident that it will pay off.  But trust me when I say that getting a companion for him will NOT hinder your relationship with him at all, and is sure to make him happy during the many hours (especially at night) while you are away.  

I hope this is helpful and I'd love to hear your progress, so feel free to write to me anytime also if you need any more help or ideas.