It is really difficult to actually gauge the baby's weight from a scan, a college was chatting to a sonographer who said the estimates could be as much as 50% out!
Don't worry about how big/small your baby will be. Your body is amazing and won't make a baby you can't birth.
As for your notes:
The cervix starts off posterior and moves anterior, either well before labour, or just before!
The os is the opening of the cervix, so you are 1-2cm dilated, but presumably cervix is still long (not yet effaced/thinned out).
Water intact is the amniotic sac.
37cm, is the height of the fundus (top of the uterus).
Ceph means cephalic (head down) and ROA is right occiput anterior (the baby is laying with his/her back to the right of you is an anterior position). Anterior is the best position, as the baby has to turn less to navigate your pelvis.
2/5 is how much of the baby's head had engaged. so in other words the midwife can feel 3/5 still.
A stretch and sweep involves the midwife gently teasing away the bag of water from the cervix with her finger, this is where she felt the head.
I hope that helps clear things up!!