Off sick due to back pain

[DJBebe]

FTM I'm 21 weeks and since a week ago i have started to have some back pains but it's very strange because the painful area is just at the top of the buttocks/last vertebra of the spine.
Initially i thought it's because of my desk chair (it's a new one and it's surface felt like concrete) but i changed the chair and i still get the pains.
Unfortunately my work agenda is very busy and I'm stuck to my desk all morning until my lunch break and then again all afternoon until i finish work and can't do much stretching or move away from desk.
I haven't mentioned it to my midwife yet as my next phone appointment with her is in 4 weeks time but if the pain persists or gets worse that it is can i be signed off work?
I have a strong work ethic and in my whole long career i don't think I've been off on more then 3-4 occasions and i would feel awkward and embarrassed to ask my dr for time off.
I don't want to let my team down but if i am in i have to give at least 100% and now it's painful even when I sit on my sofa.

[RunnerGirl123]

Work will understand, your body is going through major changes making a baby. They will know your work ethic and that you always do your best so if you're struggling then maybe calling your midwife now or speaking to your GP will be the best thing for you.

If you want to work for a bit longer, I'd try give yourself a break a bit. You aren't supposed to sit still staring at a screen for 3-4 hours at a time even if you aren't pregnant, and your workplace shouldn't encourage this either. If you don't do it naturally, set a regular timer up and make sure you at least stand up and move around for at least 1 minute when it goes off. Make yourself a drink / get a snack / shake out tired muscles etc. This doesn't mean you aren't giving it 100% at work but means you're looking after your body as well as working hard.