Picali...I know it's easier said than done, but try not to dwell on it. Doctors, nurses, and therapists are people too and some of them are just insensitive jerks who have no business working with human beings.
Several years ago when I was very depressed, I had a therapist put me down and make mean remarks regarding the sound of my voice when I cry. I ran out in a state of hysteria and never went back.
The h*ll with those people! They don't know jack. What a sad state of affairs it is when the very people we turn to for help make us feel worse!
As for your sis, sounds like she's got her own set of issues. Lying to your docs because she's mad at you? Puhleez! That's pretty low.
Keep taking the high road and remember that their opinions of you do not define who you are.
Hope you get through this ok.