Need to vent

I am currently 28+3. This is my first child and third pregnancy after two losses. I am a front office Manager for a hotel. I have been having to work alot lately covering shifts for my employees. It is currently 4:01 am and I'm at work covering for someone of course. I worked 5 am to 3 pm yesterday laid down for bed at about 9:30 and was woken up to come in at 10:45. I tried expressing to my boss that while I'm not trying to use pregnancy as an excuse I physically can't keep covering all the time. I physically get no rest,my phone is always ringing,I have no peace of mind when I clock out due to the fact that almost daily I get calls and end up having to come back to work. This has been going on basically since I started working at this particular hotel about 8 months ago. I tried asking to step down and they told me I would have to take almost a $2 pay cut and that they could not guarantee me 40 hours a week. I decided to keep my position but expressed how I was feeling and told my boss I would need to start taking it easy. Well 3+ months later and nothing has changed it has only gotten worse. I feel stuck and unable to enjoy my pregnancy. I was actively looking for another job and had been to several interviews. I got to around 16 weeks and started showing. I figured noone would hire me knowing I was pregnant while I know in my state it is illegal but working in management for 10 years i see it happen all the time. Financially I can't afford to stop working and really dont know what to do. I am very unhappy here. I got home and my back hurts,my feet hurt and are swollen, and im physically beat. The other day I got off and was experiencing some cramping which I assumed was from being on my feet all day and not eating. I ate,soaked my feet,drank some water and went to bed only to be woken up with phone calls from work. I have a dr appointment today and am going to see if there is some kind if doctors note stating that I can't be overworked like this. I am use to working alot being in management but I feel like I'm at a breaking point and noone is listening.