Feeling worried! 😟

Anyone else been told they are measuring bigger than what they are and then had a scan and baby is measuring fine? I went to my midwife other day and she said I'm 4 weeks ahead but don't look big or feel big and when had my 20 week scan they said baby was right on target for measurements I have a private scan next week that I'm paying for so will be told then as they will do her measurements just feeling worried can someone put my mid at ease please. 😕