I gotta put in my 2 cents worth here, I hope you don't mind. I don't think lying to him is the answer.. you care about each other and dishonesty is the quickest way to change that.... have you ever heard the saying..

" Oh what a tangled web we weave when we practice to deceive"

Well, trust me.. its not the answer.. the answer is to do what you must do to take better care of yourself and count him as a blessing for caring enough about you to take depserate measures to help you get well.

Take him with you to the doctor.. but tell him only one the condition that he not go in with you to be examined by the doc.. let him wait in the waiting room.. being there more for emotional support than anything... so you know you are safe because he is there.

I hope you get it worked out and that you are able to gain control over this medical situation soon... Good Luck!