It's getting upsetting and it hurts my feelings?

My parents are really hurtful sometimes. My mother says I have an annoying voice that makes me sound ditzy, and I'm too happy and cheerful. My father tells people at the diner I work at that I'm "actually a natural blonde" (haha...not...I'm a born brunette) and it's commonplace for the regulars to call me a ditz/blondie/airhead...etc now since my dad says it often. It's really quite hurtful, and I tell people that I really don't appreciate it. At dinner tonight my mom told me that I have to stop playing dumb, and that she thinks I do it so people notice me and like me. I don't. It's my natural voice and demeanour, and I'm quite smart. I've completed my first year of college, and earned a 98% overall average. How do I get people to think I'm smart? I almost come home crying because people at work (co-workers and customers alike) are teasing me.