for the last week or so ive found if i stay on a particular page for a long time or am uploading something when i come to upload it has lost my sign in and i have to sign in again and anything ive been putting on has been lost........didnt really bother me but ive just spent over an hour doing a restoration thread about my dads classic t-bird and when i came to send it,it asked me for my sign in and then all my work had gone?

anyone have any ideas?