Let it run through the night and then let us know.
It could be configuring or performing a heal, did you add any hard wired devices too?
It could also have locked up. Leave it alone for a while and as a last resort do a power cycle.
Have you refreshed the page only to see the same thing? That's usually an indicator its working, if its locked up you will see a blank page.
When this first happened to me I did a Telnet session and was able to get in and see it was indeed configuring and polling devices, there is just not enough processing power and memory capacity sometimes to do what it needs to do and allow you in so it appears busy or loading.