What you describe is not unusual! Most don't know how to handle the diagnosis and prefer to keep quiet! My advice is to surround yourself with positive people! The Un PC as you describe it is not limited to family - friends can be a bit of a shocker as well as! Basically they are not ready to handle your diagnosis. I lost a friend of 40 years - what I always knew and it didn't bother me was it was always about her and when I needed support it wasn't there!
Try not to let it upset you and concentrate on yourself and those close. Hopefully in the fullness of time and with some advice from the Counsellor you will be able to accept the way they have been and in time they possibly will catch up and realize that this Cancer is not necessarily catchy and marvel at how well you are coping.
Best wishes with your appointment with a Counsellor.