Strange things is happnen to me, no dowdabowdit!

Things like I click the remember me box and it doesn’t remember me, or threads that I have viewed show up as new. This one is even stranger,I posted in a thread and I was still logged in and it said that the thread contained new posts BUT I WAS THE LAST PERSON TO POST. Strange huh? This all started happening about 4 days ago. The only thing that I have changed is I deleted all the cookies.