Yikes, Kevy!!!!! Of course you have no control over something like that, but I realize any advice against feeling guilty would be pointless- you love Susan and so you're gonna feel bad. Let her kick you in the nads a couple of times- that should get you over it.
There have been times when I've argued with Eric in my dreams, and woke up mad enough to beat the crap out of him. It takes a while to go away, even though I know it was just a dream, the feelings seem real enough. Poor guy.