I am suppose to be due May 28th

So I just had a baby last June and I'm due again in May, May 28th to be exact. I was told when you have babies less than 12 months apart you can go early (sometimes too early). Anyhow, I went to the OBG the other day and I'm measuring at 29 weeks and I'm only 25.. has anyone else had bigger measurements at this point?