IUGR (in uterine growth restriction)

Hi, I’m 35 weeks pregnant based off my sons measurements and I was told today at his scan that I have in uterine growth restriction… His belly just isn’t matching up to all his other measurements and I’m wondering if anyone else on here has been told the same thing, they said they weren’t concerned because he’s 5 pounds and 7 ounces right now. But I just feel like I’m not doing something right or my body is failing my son. Im also a first time mom.