Login problems

When I click 'submit' to log in, it is automatically logging me in as a guest instead of under my own ID, which is Admin.
But if I click to request my password, it sends the correct password to my correct email address.
Also, I have links from other parts of my website to specific records in the database. Before, it opened the record without problem. Now, it takes me to a login page.
Any ideas as to what could create this problem? I can login to my 'testing' server just fine.
Thanks!