I'm so happy you will have one of each, and that she's healthy, yay!!!
I'm sorry to hear about the bleeding. That must be scary. However, preterm labor is not really well understood. I had no other risks or complications during my first pg, I just went into labor at 28, 32, and 34 wk (delivery) even though I had been on bed rest for 2 wk prior. So, if it's going to happen, all you can do is be informed and hopefully get to the hospital in time for them to stop it (they will not try to stop labor if you've dilated 5cm, at which point you might not even have experienced painful contractions yet).
So, having been through it, I would suggest that you pay very close attention to any "Braxton-Hicks" contractions. This can feel like anything from a "balling up" of your uterus in one place or just a tight feeling, even if it's not painful. If you have more than 4 in an hour (or if at any time they feel like menstrual cramps), drink 2 glasses of water and then lie down flat on your back, and try to relax. If you still have 4 in the next hour, eat a sandwich and then go straight to L&D. When you get there tell them you already did the water test. It will save you some time talking to a tired overworked nurse on the phone who will probably tell you it's normal and to monitor for another hour before calling back. But since time is critical, you want to avoid that, so just go. Once you're there, they have to deal with you.
The sandwich is because you will probably be there at least 3 hours and they won't let you eat once you get there.
So I hope this was helpful and not too scary...I found nothing in any of the baby books about early signs of preterm labor. They all said stuff like "menstrual-like cramps" or "heavy bleeding with clots" or "gush of fluid, meaning your membrane has ruptured"...none of which I experienced before I was past 5cm.