This happens from time to time. First try emptying the cache of your browser, that usually fixes it. (That's either on the top level of your browser preferences, or right in front on the "Advanced" tab.) If that doesn't work, you might have to delete relevant-looking cookies from the browser preferences. Under cookies, there should be one or two named "
www.theyakshack.co.uk". You'll have to log in again to the Shack, but then things should be stable until the next set of gremlins invades the net.
Sometimes the internet gets confused when you've arranged for the website to recognize you as a returning regular. Minor changes at the Yak Shack server might be the culprit, but maybe also your ISP assigned a different internet address "IP address" to you than you had in previous sessions, and you look like somebody different.