18 year old student, need health insurance asap?

I am an 18 year old unemployed student in high school in NYC. I have low TSH level. I am rapidly losing weight and need to see a thyroid specialist. I don't have insurance and cant go to a specialist to get it treated because it is too expensive. My fathers income is too much for me to get insurance but my family refuses to pay for my treatment. How do i get health insurance? What do i do? Thanks a lot in advance!