Maternity leave questions please help

I'm 25 weeks I'm due September 20th. I work at a nursing home with heavy lifting and a lot of stress on me and sometimes I feel like I'm going to go into early labor. I recently took care of this guy twice at work and he had cDef that told me after I took care of him and they no my child can catch it and so could i. What should I do. Should I ask my doctor for an early leave or should I just stick it out? I'm a first time mom and just want a healthy baby girl that's all I ask, but working this hard labor job is risking it all please help me ladies