SAN FRANCISCO, California -- A beloved San Francisco teacher battling breast cancer is forced to pay for her own substitute while on medical leave.Parent Elia Hernandez says, "She's an incredible teacher and that's not fair. That's crazy!"The teacher instructs a second grade class and has chosen to remain anonymous.Her friends at Glen Park Elementary says she suffers from breast cancer and all of the attention is causing her extra stress.That includes a GoFundMe page that has recently stopped accepting donations for her. It was started to help pay for the substitute teachers her paychecks were funding.As of now, teachers get 10 sick days per year. Then they can take medical leave for 100 days.During that entire time, the cost of a substitute teacher is taken out of the paycheck.If more time is needed, teachers can take from a Catastrophic Sick Leave Bank, which is a fund where other teachers put in donations for their colleagues, for 85 days. No extra money is taken out of that pool.Eric Heins is the president of the California Teachers Association and says, "We'd love to change it but we're working under a public school system that's been financially on starvation."It's still a hard pill to swallow, especially for those who know this teacher and who work in the school.Parent Abby Hipps says, "She's wonderful, she's a beautiful lovely great teacher. She's one of the best teachers. It's terrible."Teacher Brenda said, "It makes me worry if that were to happen to me, I have to plan accordingly and that's not fair you know."