13 weeks pregnant and thinking of disability... help!!?

I'm 13 weeks pregnant, and my doctor said that I can only work 4 hours a day x 1 month due to some risks. I'm a full time nurse in 8 hours shift. When I showed to my bosses my doctor's note, they did not accept it because they said, they don't have a job that can accommodate 4 hours work/day. they don't want me to work because if something happened to me while at work, they don't want the responsibility. instead, they advised me to file leave of absence (without pay), and state short term disability due to my condition. I've been working with the company for almost 2 years now. This is my first job ever in US too. I'm still not familiar with my rights and on how to file paper works needed. Can I file disability even I only worked less than two years? How many % will i receive from the state? Btw, I'm from CA. Please help.