Trouble navigating/posting

All my sites suddenly began to behave really weird today. I was able to post something, sort of, finally, but I can’t edit it now.

Two things are happening.

1. When I hit publish it goes to a blank page, and the URL is not complete.

2. When I try to navigate – like go to plugins – it goes to a blank page, and the URL is not complete.

Occasionally, it does what i’m telling it to do and the URL comes up immediately and I get to the page I’m looking for.

Like I said, all my WordPress sites are doing this today. Anyone got any idea why this is happening?