Ultrasound Monday

I had another check up today. I'm still 2cm but almost 3cm. I've started noticing contractions more too but nothing consistent. I asked the dr if there was anyway we could guess how big this baby was going to be based off how big I was. He said there wasn't. My belly is measuring right where the baby should be for how far along I am. But then he asked me how big Alli was when I had her and when I told him he then paused and said....well...maybe we ought to do an ultrasound. I reassured him that I wasn't "worried" about it just more curious than anything. But I guess my question got him thinking. So he wants to do an ultrasound on Monday. Depending on the size of the baby, we might be moving the induce date from the 13th to sooner. I don't know what size the baby would have to be for him to feel we need to go on and induce and I don't know how much sooner we would have him. But I can only imagine that if we do induce sooner...that it would be sometime next week. So my days of being grossly uncomfortable are quickly coming to an end and my days of sleepless nights are quickly approaching.