In need of some advice on what to do with work 
I'm currently 26 weeks pregnant, and work has been awful for the last 2 weeks. I've only had one day off in those two weeks due to my manager being off and the other two shift supervisors being off at the same time aswell as him, so I've been the only person who can open and close the store. It's been so stressful and overwhelming that I've lost 4lb in weight due to being sick from stress and not eating properly because of being sick. I'm absolutely exhausted due to the long work days (worked 70 hours over the course of 6 days) and my body is just in so much pain. My manager is back today along with one of the other supervisors, I'm thinking of taking the next few days off to try and get in with my GP and asked to be signed off. Does anyone think my GP will agree to signing me off given the stress I've been under and the danger it's put my health in? My manager doesn't seem to care what this has done to me and my baby 