I have a question that I really need advice on! I have health benefits through my job and I work full time. I have been…

I have a question that I really need advice on! I have health benefits through my job and I work full time. I have been in so much pain recently and I work long 9 hour shifts. My job is not big on letting a pregnant woman sit down for longer than 15 minutes at a time.. So I'm going to try to talk to my Doctor and see if theres a way I can get a note to go on my Mat Leave early. So long story short- if my doctor thinks for any reason that my pregnancy can be affected by my prolonged standing.. Can he tell me I can't work anymore or how does that work with health insurance? I can't lose my benefits. Sorry if this post is long and all over the place I just need advice on how to keep my benefits and keep my baby and I healthy