Hi Duckmum,
I wanted to come and reassure you. I had irritable uterus with 2 out of 3 of my pregnancies. My first and my third pregnancies (both boys!!! my middle child with no irritable uterus was a girl!!!)
Anyway I digress, I had hospital admissions at 33 weeks with both boys, from then on it was contractions all the way til delivery at 39weeks. (My dd with no irritable uterus came earlier than the boys at 38 weeks,) so you can see that irritable uterus does not mean that you will have the baby early.
I found my tens machine my life-saver! Also remember to drink lots of water, dehydration makes the contractions much worse.
I had several re-admissions with the pregnancies, but each time it settled down.
Sorry to hear of your loss. As for the "will I know I am in labour", well that is a difficult one to answer! With my first, I had a show and the contractions started again as usual, but I just "felt" different, it was another 12 hours before my contractions changed and there was absolutely no doubt in my mind it was labour for real. But the baby was back to back with me, and the labour stalled at 5cm, ended up being over 24hours of labour before he finally decided to arrive. So I had a long labour during which time it was no doubt that it was not just the uterine contractions.
My third labour, following irritable uterus was different again, for the first half hour I just thought I had a trapped nerve on one side of my pelvis, not at all like the normal irritable uterus contractions!!!!! It was after the third one I started timing them, after 3 more looked at the times realised they were 4 mins apart lasting a minute and that this was labour! Baby arrived about an hour later at home as I was too far from the hospital! The homebirth was the best of all my births, ambulance crew, midwife and doctor all arrived just before the baby did.
With my ds2 while in hospital at about 34weeks, I was at one point getting contractions 3 mins apart lasting a minute and over, the midwives were preparing me for a premature birth, but it all ground to a halt about 3 hours later!
I found with ds1 that even walking around a supermarket was enough to trigger the contractions, but they would stop after resting for a while. Being my first pregnancy I was worried constantly about the baby coming early. By the time I got to ds2, I used to just put on the tens machine and do whatever I needed to do, but rested plenty too. This helped.
I hope it helps knowing you are not alone in this.