How to get over being the "ugly sister"??

Siena
My sister is 5'11 and like 100 pounds, and people always tell her how pretty she is and how she should be a model. Meanwhile, I'm only 5'8 and I weigh 135. 
She spends a ton of time walking around in a bikini in the house; honestly I'm SUPER jealous of her beautiful figure. I love her to death and don't want to feel jealous of my little sister AT ALL, any tips? Anyone else in the same situation?
She's on the left.