What should I do about my sister?

I feel like she is evil and does not want to me excel because everytime she hears me moan about having an unproductive day or gaining weight or having friends problems, she has this smirk on her face and she then feels the need to boast about how that part of her live is going well......Please tell me ways to clear this up...she has been doing this so long now that i really do think she'd be sincerely happier if she saw me failing at life...thanks x