A - There's no such thing as false labor. Some contractions brings the baby out; others start and then rest, but they're still working. Don't let anyone tell you otherwise! =)
B - I've heard second babies are harder to tell when baby-producing-labor starts. You have more BHC, contractions come and go more, and since your uterus knows what it's doing, hopefully it's less painful.
Some things to try: if you're up and about, try resting; if you're resting, get up and about. Eat. Drink. Take a shower. Repeat. If things keep going, then you're more likely to be in baby-producing labor. =) But stop-and-start labors happen. It's just that much less to do later. =)