Being victimised by a teacher

My head of sixth form has hated me since I started here last September. I have a big family and we live in quite a large house directly opposite my school. She has made comments that suggest I'm a 'rich kid' and been implying that I'm taking away a free school place from other people who can't afford private education - as I met their entrance requirements and got in on my academic ability I don't see how this is relevant. She was my form tutor last year and constantly on my case - giving me detentions for doing things but not punishing anyone else who did the exact same thing, making comments about how I wouldn't get into the university of my choice, before I'd even sat any exams there! Other students had commented on how she seemed to look for ay excuse to punish me, and I brushed it off as not a big issue. At the end of last year she called me in to her office and said she had noticed at a running event that I was very skinny and "she had said lots of teachers had been saying the same thing" which I thought was slightly unprofessional. She went on to accuse me of having an eating disorder. As I have several close friends who have suffered with severe eating disorders in the past, I was quite frustrated that she assumed I was suffering from a serious mental health problem because she felt I was 'very skinny'. I explained that I have been thin my entire life - this is something I've always been very self conscious about because I eat far more than most of my friends, but like most of the rest of my family just don't put any weight on! I left her office feeling quite self conscious, but again brushed it off as her being concerned.

Today, she called both of my parents in for a meeting about "how the school could support me" now that my UCAS application has been sent off. In this meeting, she told my parents she thinks I have an eating disorder "because her and other teachers think I look very thin" which is an incredibly ignorant view of eating disorders - I have remained almost the exact same weight throughout my entire time at sixth form, haven't had any weight loss etc. She then proceeded to say that she is aware that I smoke - which is true, although I have never done it in public while wearing uniform, and as I am over the age of 16, as long as I'm not purchasing them, is neither illegal nor her business. She then said that I smell of smoke and "it is very unpleasant for other members of the school" despite the fact that I always apply perfume, use hand cream and chewing gum before going back into school, and nobody has ever commented on it, so I can't imagine it's really an issue. She went on to say she thinks I am "very unhappy" - despite the fact she hasn't asked me once about my wellbeing this year. She also said I wear "too much makeup" which no teacher - herself included - has ever mentioned as an issue to me. I wear the same amount of makeup as at least half the other girls in my year, but she told my parents she thinks I wear it "because I hate my body" again based on absolutely no evidence whatsoever! She also said that I 'would never manage any university course because of my eating disorder" and that I should see a professional for help with my condition - which she has no evidence of! My parents are now concerned that what she's said is true, which has made me more upset than anything as I'm completely fine! There are other girls in my year who have the exact same build as me, but it has never been commented on.

I feel that I am being victimised because of where I live, which seems to be her main issue. My parents have mentioned that she picks on me to other staff members previously, who were shocked and said it would be resolved, but it seems to be escalating. If she was genuinely concerned about my wellbeing or had any evidence of me having a mental health disorder, I feel she would have handled it differently.

I don't know what to do. Has anyone else had any similar experiences, or have any advice on what to do here?