Made a mistake with Alevel choices?

Hi, after troubles at home last year, I decided to redo year 12 with different subject. Last year i took History, English Lit, Chem and Bio and decided to change two subjects to go down the science route so am studying Chem, Bio, Maths and Art, only I'm having doubts about my choice. These feelings began around christmas but I pushed through because alot of people feel down and demotivated after a few months so I got (mostly) back on track and on top of my work. But I'm still having doubts. To convince my head of sixth form to let me redo the year I told her I wanted to study chemistry, only at the start of last year I wanted to study History at uni! Im good at art but HAVING to do it removes some of the fun and I'm really bad at maths (I havent gotten above a U so far this year), i loathe bio and only like chemistry because, at the moment, I'm good at it but out of school I have no interest in science at all, in fact it bores me. In my spare time i like following the news, playing the piano, reading, tv (i dont think that really classes as a hobby because most teenagers watch tv but i think 4 seasons of GoT in under a week and my obsession with House of Cards is the best example of commitment and dedication i have :colondollar:

)and learning russian. Spot the trend? My interests are totally unrelated to my school subjects which i have no passion for and doubt if i can study just one for three or four years. If i redo alevels I'd have to pay quite alot and i dont know what to do! Where can i get help? My school is useless, I spoke to my mentor and when i said i had no interest in my subjects or science he said 'have you considered engineering, architechture or pharmacy?' It's like talking to a brick wall.