Bfriend, I'm certainly no expert, but it almost sounds as if she feels threatened by you. I wonder if your successes have caused her self-esteem to dip? Not that you'd do anything intentionally, just a thought.

People like your sister just wear me out. IMNSHO they suck all the life from the people around them. Good luck to you, and bravo for your patience, endurance and continued good efforts. I think she needs you whether she knows it or not.

I always wished I had a sister, but wonder if there might have been competition or contention that would have caused feelings. *shrug*