Hi Rae,
Congrats on the preg by the way. I recently have had #2 and whilst the pregnancy and the birth were an absolute dream (i.e 30 min labour, no drugs, no tears, perfect baby, home next day.) i too had my doubts at the back of my mind, for the whole 40 or so weeks...........
I had third deg tears with my DD #1, retained placenta, massive blood loss (which resulted in 2 x blood transfusions) and a risk of a hystorectomy (sp?)- (which i didnt find out till 2 days after i gave birth that it was even discussed). Like you, i fell pregnant incredibly easy, we wanted a sibling for our DD, and we wanted another little poppet to endure. Pregnancy wasnt my fear, i generally have easy going pregnancies, it was the labour. How can i go thru that again, what if i loose too much blood, what if i cant push anymore, what if, what if, what if. I believe i covered my fears, and pretended labour with DD #1 just didnt happen, it was ancient history now and it couldnt possibly happen again !!. But every time i went for my antenatel checkups, i would get home and compare my pregnancy notes to that of pregnancy with DD #1 and i would wonder for the next week or so what we had gotton ourselves into. I had that nervous knot feeling in my stomach EVERY single time i went for any appt.....it only lasted a few days, but still it was there.

I apologise if im rambling, all i wanted to put across was, its perfectly normal what your experiencing. My mother is a nurse, so every appt i had, every test i had to go for, i brought her along. Got her to ask questions too (she was with me during my first labour, so knew what i went thru). I found her medical background really helped ME in understanding what i went thru, and what would happen if i went thru it again. Talk to your OB, talk to DH, talk to us. And like someone else said, trust your instinct.

But, more importantly, enjoy this pregnancy. Its such a wonderful time, it will never be you and Ella anymore with bub #2. Enjoy her, enjoy this time.
Good luck !