If you are working through what are supposed to be your lunch breaks, STOP. If your shift includes an extra half hour of unpaid time, that is your meal break. You must stop working through it. You are donating your own time, you are volunteering your break time to your job.
If anyone gripes at you, just say that you'll be there in just a few minutes. 30 minutes, after all, is pretty short. Just enough time to gulp a few bites, do some quick meditation or prayer to restore your soul/spirit, pee, maybe make a quick call home. Obviously, if anyone's life or limb is threatened during that time, you must get back to work instantly.
However, when you don't get time to take your UNPAID meal break, you must make sure your employer pays you. It is illegal to not either make sure you get that UNPAID break or pay you for working through it, one of the 2. I think you should take this up first with your boss to give her a chance to rectify the problme, then Admin if no satisfaction with your boss, then OSHA or US Dept. of Labor if no help from Admin.
As for unpaid rest breaks, I was shocked recently to learn that very few states require employers to give them to adults. Some states require them for minors, if I remember correctly.
I wonder if it would help to look at the reasons you don't get breaks. In other words, assess the problem. Are you overwhelmed by the doctors' demands, the patients' conditions, or the expectations of Management (who are, I'd bet, routinely getting their breaks)? Or is it some other causes?
Are there some changes you and your coworkers could make to ensure that you all get your 1/2 hour meal breaks?
I wish you good luck. If you hit upon a solution, do let us know.