What the crap is wrong with my sister?!

I have a sister that is 3 years older than me and she flirts with all of my crushes(that are three years younger)...it seems like they like her back, too! I'm so jealous because she is a lot prettier than I am. My parents half believe me when I say it, and I'm so frustrated!!!! My parents call me boy crazy, and so I don't think they believe me. Also, I have depression so my sister makes it worse, help!

btw my parents already know I have depression and so does my sister.

You might want to give the link below to your parents. It explains why brothers and sisters compete and what can be done to change it.

http://www.med.umich.edu/yourchild/topics/sibriv.htm

she just wants to mess with you are compete or some thing and for parents they just think that its just you guys having fun and for what too do well...............................................I DUNNO I AM NOT A PSYCHATRIST JUST TELL EVRYONE AT DINNER A ARGUMENT AMOGST A FAMILY COULD BE GOOD EVRY ONCE IN AWHILE