Few! Not just me then! (not pregnant yet but have been twice).
That's your rational side freaking out!
As soon as your mind gets in the way, it finds all sorts of problems and negatives about the pregnancy, because it's such a big thing.
When I fell pregnant the first time I didn't know for 18 weeks (irregular period may I add, and fed up with testing and getting negatives).
So obviously I wasn't freaking out, but my deep self must have sensed it, because I suddenly got a real sense of family, ie, I phoned my mum (who usually gets on my nerves bless her) on Christmas eve nearly in tears because her, my dad and my sisters weren't there with me. Normally I wouldn't have cared that much.
Also I suddenly developped a nursing, nurturing side (out of character), I was delighted when my friend asked me to look after her fish for a week, and sad when I had to hand him over 
I became the perfect housewife and spent hours preparing my christmas menu. Very strange.
The day I found out, I freaked out, cried, remembered that I had been drinking alcohol (not too much though) and was convinced I was going to be a crappy mum.
Now I can't get enough of my children, would like one more, think children are the best thing in the world, and love every aspect of mothering.
So don't you worry, it is normal. And it will come with time. xx Good luck, and try not to think about it too much, relax and accept the way you feel. 