You could email or Call the admissions office at WP. They will help with answers. I was constantly in touch with the officer for my son, with multiple questions while waiting for his nomination, ect.... he actually told me that my son received an "Appointment" for the Class of 2013 before he even received the official folder.
That's weird. Usually the WP candidate portal updates pretty quick for me. It shouldn't be a big deal though. I got a nom to USNA almost a month ago and the candidate page still doesn't say I have one. Just talk to your WP rep. I actually found out from my Navy RD that I had an LOA like a week before it finally showed up.
What matters is that you know you have the nomination, and if you've received a letter, WP probably has too. Just as long as everyone's on the same page (figuratively speaking) it's all good.