Well yeah, second time around you'd think I'd have a clue, but I don't

I have been having period type pain since yesterday, it has really hotted up this morning. No tightening whatsoever with it, just period pain down low, that comes and goes. I do think I've been having ligament-stretching pain over the last little bit, and it definitely feels different to that. A couple of weeks ago I was actually having very mild contractions (tightening, with discomfort) and BHs. Those seem to have died down (thank goodness!), but I'm not sure what's going on now.

What is this period pain? Another type of stretching? Baby engaging (although DS engaged by 32 weeks, and I don't remember feeling anything like this!)? Pre-labour? I don't think I really had pre-labour with DS, once my waters broke I had about 2 of these types of period pains in an hour, and then BANG full-on contractions every four minutes. So I have no idea what to look/feel for really, in labour starting, as PROM gave it away last time LOL. I am at slightly higher risk of preterm labour, but I know that pre-labour can go on for weeks.......if indeed that's what it is!

Any ideas would be welcomed! TIA