Hi Erin,
whats the saying you can choose your friends but you can't choose your family!
Could be a case of sibling rivalry? Maybe she feels that you take attention away from her.I know it sounds crazy but when my sis became disabled I resented her for it and struggled to believe it could be happening. Ok I was 16, but sometimes people just dont get over the rivalry.
My sis and I are very very close now. I think because Im now ill I can see it from her side.
I say to people walk a mile in my shoes......cause I know I bloody can't.
Hope you have calmed down!
Love
Rach