Can't add anything to the good advice already given on here op.
Like others, I don't know if it will be a matter of forcing unvaccinated people to shield. It may mean that, but it wouldn't be some sort of punishment, would it? If you're unvaccinated and pregnant and therefore more vulnerable, of course, if things get worse again, you may be asked to shield, just like people with other conditions will be.
I don't think you should be forced or coerced into getting the vaccination at all. But then, you do take on some of the responsibility for being more careful than other pregnant women who are vaccinated. That isn't to punish you, but surely it's common sense, to keep yourself and your baby a little safer through other means, (ie not going out and possibly shielding when asked to).
Congratulations to you though and do not feel pushed into getting the vaccination if you don't want it. People stayed in for huge chunks of last year, during pregnancy and with young babies. Not fun, but doable! In some ways, you don't want to be out and about that much with young babies or during the end of pregnancy, so you may have to stay in and maybe you won't mind.
But, I think people maybe reacted strongly on here as it did sound as if you wanted to go out a lot unvaccinated. You have since clarified you won't be, so, to a point, does it really matter to you personally if you have to stay at home more than others, seeing as you were planning to anyway?
Congratulations again 