How can I get into my face book it will not load

Basically, for any site:
Try again in a minute or two.
Clear cache and cookies and reboot.
Try a different browser. Maybe keep IE8, Firefox, and Chrome on your desktop.
Assume that sometimes, usually in the middle of the night, maintenance is going on, and you can't always get on to all sites.
Someone in your house messed with your ID.
Someone not in your house did.
Something totally off the wall happened, like a Facebook name the same as yours got switched or combined (happened to a relative of mine.)
But these are in order of probability, pretty much.