jdemora,
Congrats on your new addition! Looks like a lovely pup...that said, 5 weeks old is a little young to be taken from the mother. (no offense intended) Labrador Retriever's are kinda' late starters, most breeders prefer to keep them (but weaned) with the mother up to 8 weeks. I've found that Lab pups taken too young often develop into "needy" type adult dogs...I've raised quite a few (I currently own six!) BTW, for the first two years, Labs are basically out of their skulls "foolish" and can be a handful to train if you aren't firm and consistent with them. After about age two they start to calm down and grow-up...although they still require lots of time and at least an hour or two of vigourous exercise each day.
Now that you have her? You need to make sure she is well socialized and not left alone for long periods. If there is another dog around, it would be very helpful to have her play and interact with him/her as much as possible, especially as she matures. This also helps to socialize your puppy and will give you a much more well-adjusted dog. Poorly socialized dogs usually end up being either aggressive fear biters, or the cowering "fraidy-cats" type, that can also bite out of fear.
Get her on a schedule as soon as possible and all involved will be much happier. Every time she wakes up, eats or drinks, you should immediately take her outside to do her business. Pick a spot in your yard that she will come to recognize as her "bathroom." Consistency is the key and if you remain so, potty training will be a breeze.
To prevent your pup from developing "separation anxiety" don't make a big deal of her when you leave home or come back and get her used to being left alone for short periods. A "safe" area, like her crate is recommended. As she matures and can be left for longer periods you can do away with crating her. Labs are barkers and if they develop separation anxiety, you can become very unpopular with your neighbours really fast...or with your wife after Sierra eats the new couch or her new shoes as a result of her fear and anxiety at your absence!
Most importantly, enjoy her and love her! I love my Labs, although having a 120lb Lab jump on your 'nads first thing in the morning to go duck hunting takes some getting used to!
Sorry if I sound a little preachy, but of late I've seen too many absolutely beautiful Labs end up at shelters or are euthanized because first time owners or people looking for a status symbol can't handle their dog anymore. In no way, shape or form am I insinuating that you are such a person!