Apologies if this is an absolute essay, just want to give adequate context!
I am currently 10 weeks pregnant. This is my first pregnancy. It wasn't planned but it was a happy surprise.
Less happily, I have been nauseous 24/7 since I hit 5 weeks. Started cyclizine at 6 weeks which took the edge off a little but it has really ramped up the past week. Am still vomiting most days despite barely leaving my bedroom. Most smells will cause me to vomit so I'm just doing my best to avoid triggers. My husband has been bringing me small meals in bed as I cannot go in the kitchen. I am knackered and miserable but feel so grateful to be pregnant and to have the time to rest.
I am a HCP. My contract ended at my last job when I was around 6 weeks pregnant. My last few shifts were absolute hell. The team were amazing and I wasn't allocated any of my own patients, so everyone was cared for safely, but I wasn't able to do my job effectively because of the sickness (spent most of the shift with my head in the loo).
I am due to start a new job when I will be 13 weeks. I interviewed and accepted this job back in March, before I became pregnant. Perhaps naively (!), I have been clinging to the hope that at 12 weeks I will suddenly feel wonderful and able and so it would be no problem going back to work.
I called occy health last week to discuss this who told me that I would need to push back my start date via HR if I'm still too sick to work. It feels so unprofessional to request to push back a start date that was agreed months ago so late on. I don't even know when to request to start instead as I cannot predict when things will change. This added to the fact that I'll only be there for 5 months before going on mat leave makes me feel like I'm going to be very unpopular! 
Does anyone have any sage advice? I want to try to show up on the agreed start date and muddle through, but patient safety is my priority and everything I've taken that approach to so far has ended in me vomiting in public then hobbling home looking rather unkempt...