Wow, I think we must be twins! I have a 20-month old who is also nursing a lot, and I'm also due March 2nd! (I put March 1st in my siggy because it's dh's birthday, and I like that date better, lol!) We started to ttc partly because ds was sleeping through the night, (well, I also thought it would take a few months longer, too!); but, now that I am pregnant, he is waking a lot to nurse again. Go figure.
I'm just taking it one day at a time and see what happens. I am open to tandem nursing, but if things get too rough, I will put some limits on nursing. If he doesn't snap back into sleeping through, I will most likely try some gentle night weaning. I guess it's a balancing act between his needs and my tolerance.
Good luck working it all out!
Melissa , wife to Tom , mom to The Baron , the Bean , Little Bear , and Baby Beaver