Working 53 hours a week in 3rd Trimester

I'm a nail technician, 31 weeks pregnant & not high risk. I currently work 43 hours a week, but my boss wants me to come in an extra day which would make it 53 hours a week that I'd work. I am trying to work up until I give birth because I work off commission. I was just wondering what everyone else did when they were in their 3rd trimester & if you think that's too much? I am also going to talk to my doctor about it, but just wanted to hear about others experiences. Thanks!