My wordpress.com blog tries to logon to my self-hosted wordpress install at my own site...

I have a blog e.g. myblog.wordpress.com
I try to logon to its wp-admin but then it redirects me to the login at my personal domain e.g. www.myname.com which also has wordpress but is self-hosted on a purchased hosting account.
How did I create this mess and more important, how do I go about fixing it?
Thanks!