How do I ask my doctor can I take early leave?

I was thinking about waiting til my 8th month which is just two weeks away. But I feel like work puts to much stress on my body. I’m constantly doing things that I feel I’m overworking myself. They keep wanting me to do things that they know i can’t do. They want me to carry heavy things, pull heavy pallets, moves racks and tables. I’m constantly feeling sick at work, I’ve had plenty of fainting spells and now I’m constantly dizzy. I always have to sit in the break room when it’s not my break time and I can’t keep doing that on top of it Im missing work a lot and I can only get a certain amount of absences which I’m already at the max. They fall of every 6 months which my 6th month is in October when i am due so while I’m gone they will leave. I don’t want to get fired right now for me having to miss work. On top of that i keep getting Braxton Hicks while at work because I stand for long periods of time. I know it’s normal to get Braxton Hicks but I know my body, I get them way to often at work and it’s uncomfortable. My body always feels tired and worn out the second my shift starts. I don’t want to be dramatic but I don’t think working my last month or two is a good idea. I’m a very petite person and I’m aching everywhere as well 30 weeks pregnant. It’ll only get worse idk if I can do it. I do get paid maternity leave.

I know someone can’t “make” me do something especially while pregnant but the managers I work with picks with me 24/7.. I know it sounds crazy but it’s not. I tell them I can’t do it and they let it go it’s the fact they keep trying to make me do it knowing I can’t.