Looks as though most of the site is down now.
I was browsing my packages and left the browser open for about 23 hours. When I returned to the session and clicked my username, I was redirected to "https://nuget.org/Errors/error.html?aspxerrorpath=/users/account/LogOn". I clicked the home link and then Log On and was shown the error page again. So, I clicked the home link and then Log On a few more times to see if it might be a valid exception and was shown the error page again. I did this process again to see if I could reproduce it and I could. I hope I provided enough info. I know exceptions happen and I just wanted to say thanks for providing the awesome solutions!
This is fixed. You are now redirected to a log in page (since your session has expired) and when you log in, you are redirected to the profile page.