How do i tell my parents im not doing well in school?

I just did first year university but was only taking some courses and i didnt do well at all...my parents are indian so they have such high expectations of me doing well but i only passed 2 classes and they spent to much money just to get me through the year...i tried my but off and i know there not going to believe me but now i dont know what to do...there indian and so my dad wants me to go into optometry or pharmacy and really doesnt give me much choice but the science courses ive taken just dont amuse me and i find it boring, its hard telling them this because my older brother is becoming a doctor but i just dont understand it...what should i doo? i got 2 Cs, 4 Fs and 2 Ds....