10.8.4 log-in issues (can't log-in)

I just updated my MBpro to 10.8.4.

I'm lucky I have another computer I can use to write this from.

Right now I CANNOT LOG IN. I'm presented with the log-in screen and when I select my user (I am the only user) and enter my password - screen goes white - gives me a spinning gear - then black and back to the log-in screen.

I know it accepts the password because it doesn't do the little shake you get when you enter a password incorrectly.

I also cannot get in from the guest side either.

I feel like I can spend the next hour trying to log in and get nowhere...

thanks!