Baby's HC & BPD is less. Should i do?

Hello! Im pregnant with my second baby (first baby girl is 1.5yrs old with C Section). My LMP is December 22 but when we did scan at 5 weeks 5 days embryo was not seen and i was having brownish discharge. but later it stopped and the reports were fine but the growth was one week late so my Gynac said we will consider Dec 29 as LMP. But the NT scan reports were as per Dec 22 LMP(matching my original LMP) thats why i gave that LMP for Anomaly scan yesterday. But the radiologist said that HC and BPD is below 3percentile but rest everything is normal. My quadrupl marker was normal. What should i do? im stressed. I have travelled to Kolhapur but i will go back to Wardha ( where my treatment is going on). My gynac has suggested to take Wagner tablets twice a day for 15days and then visit. During my first child also the head was small and below 5percentile during 8th & 9th month reports but my first baby is perfectly fine. What should i do? please check my NT & Anomaly reports.