twin early delivery question

After mummy's who have had twins 29-32weeks 
My question is what were the signs you were in labour and how did you feel the week leading up to going in to early labour 
Also if you had a baby before you twins is the tightening and pains of a early labour as strong as a full term 
My doctors had told me my cervix is starting to open and I haven't felt no pain he believes I won't make it past 32weeks and he has given me steroid shots 
I'm worried I won't notice the signs until I'm in full blown labour my last child was born at 35+5 and I didn't realise I was in labour and had him in the emergency room because there was no time to get me up to the ward :(