Hello Honey,
Well believe me I know where you are coming from. DS started with BT resistance a few weeks ago even though I already cut his nap gradually back from 2 hours to 1. So we went no nap. His nights started out at 13 and slowly over 3 weeks went down to 11. He took a few naps in that time but every nap robs night time sleep, and this is where we are right now.
I don't think 12 hours is enough TBH Hun, but what I have learned recently is that what your plan of action is depends very much on the temperament of your LO. Some LO (like DS Sam who is 'Angel') can take no nap days and remain happy. Others simply can't get through the day without a nap and will melt down in the afternoon unless they've had one. The parents of the latter type of Toddler have to stick with a nap and accept the shorter nights, for an interim period until the LO can handle no nap. The 1-0 transition can take some time.
My advice to you would be to cut the nap back to 45 and see where it gets you. Putting down at BT later gets a better result/quicker settling time. If no joy then I'm sorry to say

there is no other choice but to go no nap, with some nap days thrown in here and there when she needs on/will take one. With Sam he doesn't get more sleep in 24 hours when he naps but it helps him feel better to spread the sleep on that day IYKWIM

I hope this is helpful somehow

but quite honestly the 1-0 is a really tricky transition and I am also still trying to figure out the best way for DS to get through it (see my own thread

) as are dozens of other Mammy's on the Toddler Sleep forum right now
There is a 1-0 support thread if you'd like to join

Other than that all I have to say is CONGRATULATIONS on your pregnancy and I'm sorry the timing of this is bad for you

I bet you could scream!
(HUGS)
Vicki.x.