I had a friend in a similar position (working in retail, on the floor, 9 hour shifts) and her doctor placed her on bedrest during her first pregnancy when she had pre-term labor.
Irregardless of how tired you are or how hard it is on you (unfortunately) doctors will not put you on bedrest/medical leave unless they are concerned about the baby’s health. (Though, at the end of one particularly rough pregnancy when I had a physical condition which made it essentially impossible for me to walk I did have a doctor who wanted to provide me a short term Disabled Parking permit so that I wasn’t trying to walk from my parking garage to my office. And that was about my health instead of the baby’s…)
If the doctor is concerned about pre-term labor then you could be placed on bedrest. Then you have to file with your employer for short term (or longer term) disability medical leave until you reach “viable” which is 36 weeks.
Your employer’s requirements may vary according to the State that you’re in – but the FMLA (which is Federal) act gives you 12 weeks.
If your leave (remaining time until you’re 36 weeks) will be longer than 12 weeks your employer may not have to guarantee your job will be there for you at the end of your leave – but you’re protected for some time.
I had another friend (in an office job) who was fired while pregnant – and because most States are “at-will” hiring States she wasn’t able to do anything about it. Had nothing to do with her performance or ability to do the job..they just worried she wouldn’t come back after delivery and pro-actively fired her.
Yet another good friend was a hair stylist who worked 4 days, 10 hours standing each day. She worked her whole pregnancy standing for those long hours and didn’t have a problem… but I know she had a lot of swelling (esp. her 3rd trimester) and was pretty tired at the end of her days.
So—it’s partially out of your hands. It depends on whether you experience pre-term labor or not. Then it depends on your employer and your medical leave policies.
If it helps at all..remember that the 1st term is when most women feel the most tired. Once you get into the 2nd term (think..16 weeks onwards) most women get more energy. It may feel impossible now..but you might find yourself with more energy and ability to make it..at least closer to your 3rd term. And perhaps you employer would be willing to let you forgo lifting and pushing heavy things for the benefit of having you around longer.. Might be worth a talk with your supervisor…
Good luck..and best of health to you and your baby.
p.s. Last but not least – both my SIL and I had jobs that required a lot of standing. She’s a High School chemistry teacher, I travel/present—think of OJ running through the airport..that was me, but waddling as fast as I could manage!!
We both had hyperemesis gravidum (think: non-stop puking, losing over 20% of your body weight) ...we both made it through..the standing and the puking..and neither of us ended up having to go out on leave.
Looking back I wonder how I did it..but I did. And it was worth it (because I needed the medical benefits!). We each had 3 pregnancies and my SIL had HG for all 3! I think she deserves a medal! Maybe you’ll find some unexpected strength to make it through, too.. but not at the expense of the baby’s health. I hope you know what the signs/symptoms of pre-term labor are and are watchful.