Hi blondegirl,
You dont come up as a guest, you are a hidden user.
Anyway what you need to do is this, go to your profile, then click on Account Related Settings which is in the menu at the side, then a new page will appear and you need to tick the box beside 'show others my online status' and then remember to save the changes and then bingo that should be that, you will then be online without being hidden!!
Hope this helps.