There is no federal law covering meal breaks. I did assume that OP has access to a bathroom or small breaks. There are 6-7 states with laws regarding breaks. They vary from 10-15 minutes for 4 hours worked or must be given reasonable time to use a restroom. I'm not aware of any state that requires an actual 30 minute meal break. Only that if a break is under 30 minutes it must be paid or you can't subtract for meal breaks if employees are not relieved of all duties.I agree about the payroll thing but I dunno if I agree about the break thing. Maybe it's a state law here but there is DEFINITELY a law that they have to give a certain amount of break time. Do you mean you don't get any break at all? I've had jobs that do lunch break and do something weird about the other breaks. But I seriously have had no job over 6 hours a day that does no break at all. And these aren't voluntary breaks- you've got to take them to comply with company rules or laws. Also, If your company has a break policy then someone is probably jerking you around. Do you have handbook?
Congrats on your pregnancy. I realize this is not a perfect world. But I'm not sure you should hold off on telling your supervisor. It's your responsibility to advocate for your health and the health of your fetus. (But possibly in HR, you won't be at risk. Most jobs I've had have involved chemicals or contagions.) I'd say if they are going to fire you over this anyway- I wouldn't want to stay there. It may be your "dream" job, but it won't be a long term prospect for you.