I really hope the job at the closer location works out. What you're dealing with now is dangerous to both your physical and your emotional health. Not to mention a risk to your career and license.
If you don't have professional liability insurance
, I encourage you to get some (should be around $100-$120) immediately. This kind of employer will not be on your side if anything goes wrong. In fact, they'd be more likely to toss you to the wolves, because all they care about is the bottom line. You need someone in your corner! (Get the insurance, even if you find a better job. It's cheaper than one hour of attorney consultation, and the peace of mind is worth it, even if you never need their services.)
You said your boss might say something different if she had to do your med pass. I doubt that she's interested in reality. And I know she isn't interested in your well being. You can bet that she's not taking the kind of pressure you're talking about home with her when you know she's sending it home with you.
Find a new job. Give notice. And think about her having to scramble around to locate a new lackey. Maybe after a few weeks of juggling problems and covering holes in the schedule she'll be nicer to the new hire. But, I doubt it.
No job is worth putting yourself and your family in harm's way. I wish you the best.