The same kind of thing happened in my first Dynasty attempt - she ate about 5 watermelons during the "nausea" period, but still had a boy! I know Pam recommends more like 8-10.
And yes, it will give you multiples if it will max out the house; in another challenge, I had a pregnant sim with 2 empty slots in the house, then someone moved out right before Mom went into labor, and she had triplets. I always had the impression the time to listen to children's music and watch the kids channel on TV (also important) is before Try For Baby...