Nothing in my entire wardrobe looks good on me! What do I do?

It's terrible because my closet is stuffed full of both my clothes and my sister's clothes (which we usually share) but everything I wear looks horrible on me. I have a 23 inch waist and I believe 30-31 inch hips and every single thing I try on makes me look fat and/or childish. It's horrible because everyday I look into my closet and I feel like crying because I have absolutely nothing to wear that makes me feel confident and fashionable. But I love fashion and up until recently I felt that I had a good sense of fashion and style, but now, what with my wardrobe predicament I just feel like an unfashionable fat slob. I shouldn't feel this way because I exercise and I eat right but my confidence is suffering and so is my self esteem. It's so bad that my whole day is ruined as soon as I look through my clothes. Also; my family doesn't really have enough money or resources to support a complete wardrobe revamp so I'm stuck on what I should do. I really feel like I can't go on with my current wardrobe; what should I do?