Pottermore has recently undergone a lot of changes. It is no longer as interactive as it was, and it is now geared at mature readers, who only really joined to find out what house they were in, rather than new/younger readers. When Pottermore first launched, it was a big deal because this Hogwarts house sorting quiz was legit, created by J.K. Rowling herself.
Now with the new changes (although the algorithm of the quiz remains the same) there is the option to retake the Sorting Hat quiz. A lot of users are curious to see if they would be resorted into the same house...and a fair few are gravely disappointed. However, I want to make it perfectly clear that you do not have to retake the quiz...and if you do and are unsatisfied with your new house, it is still possible to reclaim your original one.
Here are three simple steps from your resident Ravenclaw to help you reclaim your original Hogwarts house:
1. Create a new Pottermore account with the email you originally used to sign up for Pottermore.
Already created a new account with that email? Is it the one you had your new house mishap with? No worries! Delete that account and then create a new one with the same email. You can delete your account by going to the "My Details" page.
2. After verifying your account (Pottermore hates Hotmail, your verification may never come) sign in and choose "Reclaim Your House."
3. Type in your old Pottermore username!
If you do not remember your username, check your old Pottermore emails, or email email@example.com, making sure it is from the email you used to create your original account.
These three steps have been tested and should hopefully allow you to recover your old house and put an end to any identity crisis you may be having. If you have any further questions, please don't hesitate to ask, or check out the Pottermore FAQ page.
Unfortunately, as Pottermore no longer caters to younger members, those under a certain age (I am not entirely sure what it is) have had their accounts and information permanently deleted. Yes, it is exceptionally messed up. I am so sorry.
All the best for your Hogwarts adventures ahead!