Jealousy is such a tricky feeling. It really doesn't matter how well-off your sister is. Usually, if you felt better about yourself in general, you'd be happy for your sister rather than resentful or jealous. So the big question isn't "why does your sister have what you'll never have?" it's "what has lead to you feeling that you'll never have what you want?"

Really, it's ok to be jealous of her. It's not your fault. You feel terrible about yourself, and her successes are making your wounds viewable to you. That's actually a good thing because it means you get to see and work to resolve those wounds!

It's not so much about what you feel your sister has, but what do you feel you don't have?