Bridge...I don't think you're screwed. Your analogy of "shooting Bambi's mother" did give me a smile, since you are obviously very sensitive to this girl's feelings. But she sounds very clingy and too eager. There is still time for you to be honest and up front with her, without coming off as a cad. Even if she is a coworker, you can still be strong, honest, and offer friendship. Don't let yourself get into the cuddling and kissing again unless you want to bury yourself.
Patty