More late-pregnancy body weirdness

That episode of "more than over-eagerness" that I had last Wednesday night reappeared last night and I must say, this is not amusing. We were out running errands before church and I had some very long, very intense episodes of severe discomfort, mostly focused in my lower back and also present in my low abdomen. They were severe enough that my eyes watered and we had to abort our plans to go to church. This was somewhat more intense than the version of this experience I had on Wednesday. I don't recall nausea that time, and this time I was somewhat nauseous.

Contractions certainly do occur during these episodes, but they happen painlessly all the time, and even during these episodes of discomfort, they don't appear to be all that related to the episodes. The episodes last for 6-10 minutes and when they abate, they don't leave me feeling normal, as I understand that contractions would normally do; instead, they leave me feeling a duller, lower-grade ache in the interim. Each of the two times, these episodes have intensified and waned over the course of about an hour. Then, I return to absolute normal.

I'd be curious to know if anyone has any thoughts on what these episodes are and whether they serve some useful purpose. Last night, I called Labor and Delivery to ask what this was. (My mom, sister, and soon-to-be brother-in-law will all be coming from about 8 hours away, and I want to give them as much notice as possible once I figure out that I'm really in labor - whenever that happens - so I thought calling labor and delivery might help me to clear that up.)

The nurse listened as I described this experience, and she said that it sounded like early labor but she definately didn't feel confident enough about it that I should call in my family. (Actually, my mother called during one of the more intense episodes of pain, so she and my sister were already on alert.) But she said that sometimes people have something come on strong like this, then the contractions will "peeter out" and not come again for a long while. She called this "latent early labor." But I'm still not at all sure that the pain came from the contractions. It seemed more to me that the contractions were just happening from time to time amid the pain. The nurse said that if this is, indeed, "latent early labor" it could last for days, and I suppose that I won't have any clarity on those episodes until I have a more normal experience of labor and can compare them.