Assalamu'alaikum, I understand your worry, it's natural to feel anxious when things aren't exactly textbook. The good news is, a lot of mums have gone through this and their babies turned out perfectly fine. From what I've heard, sometimes baby boys especially tend to have slightly bigger heads relative to their bodies, and it can also run in the family, so if you or your husband have bigger heads, baby might just take after! The important thing is what your doctor already checked: no fluid buildup in the brain is a very good sign. A friend went through something similar at 28 weeks and her scan showed the same thing, and her baby was born healthy with no issues at all, sometimes babies just grow at their own pace, and the repeat scan in 2 weeks will give clearer picture of the trend. Do keep that follow-up appointment and chat with your specialist when you're referred, just so you have full peace of mind and they can monitor closely. Wishing you and baby all the best.