I'm going to call my co-worker disgusting
Why do you think she is disgusting?
She thinks she knows more than most doctors about medical matters
It seems your co-worker may be annoying, but she doesn't sound disgusting. In any case, it's rude to say mean things to co-workers.
I will try to not be rude for the sake of my job but I still think she is the rude one and not me.
You can think what you want but it is not always appropriate to say it out loud. At work it is especially not easy to deal with some people, but keep your chin up and just let it slide off your back per say.