Confused. Big belly small baby??

Hi so my last pregnancy ended at 33 weeks because of severe IUGR. This pregnancy they’ve kept a close eye on me due to similar complications. Since 20 weeks I’ve been scanned every 2 weeks. Baby has echogenic bowel and I have positive antibodies. I’m now 29 weeks pregnant and they’ve told me at scans that my baby is measuring small again and he’s on the 10th centile but just yesterday when my midwife measured my bump he’s showing that hes on the 75th centile?? Which one is right I’m so confused. Is my bump just bigger this time or is he actually growing well? I have another growth scan coming up on Monday in the fetal medicine department. Has anyone had this??