I'm at a loss of what to do

Hey mamas! So I have a situation that I've currently been dealt that I need advice on. I'm currently 7 1/2 months pregnant with my third child and I have gestational diabetes, so my pregnancy is considered high risk. My entire pregnancy I have worked at a donut shop and am still currently working but here is my dilemma, I've just been diagnosed with diabetic neuropathy in my feet due to not getting off my feet for hours at a time and I'm talking like 6-7 hours straight of constant standing and walking during my shift. I'm part time so "legally" I don't get allowed breaks. Weply doctor said my last appointment that I've been on my feet too much cause my feet are purple and bruised, plus they go numb after I get off work therefore he said I have to take breaks and get off my feet more often. The problem is my boss refuses to work with me, I even offered to switch shifts to open the shop from 2 a.m to 9:30 because it can allow me to take those short little breaks when necessary. The shop is a high paced job at times and I get that but I'm the sole provider for my three kids (father up and left after a ten year marriage to another woman and doesn't provide nor see my oldest two) so I can't afford to quit and it's too close to my maternity leave to find another job my boss says she will be out money if she gives me a few of her shift (morning laid back shift) and she is just not going to do that. What would y'all do? I'm at a loss. I have zero family to help me and child care is outrageously expensive so it's hard to find a babysitter that works with my schedule plus is reasonable on a single mom. I feel like the world is against single parents.