Xray tech and pregnant

Im 5 months pregnant and I'm the only xray tech in my office. They r killing me with back to back patients and there's no one else here that can do what I do. I'm hot and when I'm on my feet too long I start cramping. Today has been really uncomfortable. I don't get breaks or even a lunch break. Should I keep working or just quit now? They haven't even started looking for someone to replace me. I hate this place and it just stresses me out!