Well, I have no idea how to banish the fear, if that's what you're asking. I'm currently pregnant with my second child (ds1 pPROM @ 20 weeks and born @ 30 weeks) and things have been going normally. But even so, with every milestone I crossed, I was very fearful. During my 20th week, I was convinced I was leaking fluid. In my 30th week, I was convinced I was having contractions. I just had to remember to breathe and remind myself that what will happen will happen. I couldn't control any of that stuff with ds1's pregnancy and I couldn't control it with this pregnancy. That usually did a pretty good job of calming any panic down, at least for a while.
FWIW, I'm almost 32 weeks now and I'm counting on making it all the way this time!