Log In Help

I have the newest version of wordpress. I cannot log in. I am not sure what has happened but I will describe the events leading up to it.

I changed the theme and there was no gray bar at the top to log in.

I went to the generic http://wordpress.com/wp-login.php
to log in.

It did not accept my user name and password, so I reset it. It still doesn’t work. Now it keeps saying my user name and password do not match. I cannot seem to get this in.

My questions are two fold:

How can I successfully get into my blog
How can I create that login tab at the top of the blog

Thanks
Susan