I would like to know if I suffer from ptosis?

One of my eyelids is saggy and droppy and I'm really worried because i might have ptosis. It doesnt run in my family and I wasnt born with it. I started noticing it 3 years ago and since then it has gotten worse because it wasnt this droppy. What should i do ? I'm so worried! And if i suffer from ptosis how much does the surgery cost? Are there any other cures if i cant afford surgery? Thank you!