Ughhhh😖😖😖scared

At last appointment my dr said I was measuring a little small and would check next time and if I was still small order an ultrasound. So today was the next appointment and I'm 31 weeks tomorrow still measuring 28 though and I had to schedule an ultrasound and now I'm just worried! Anyone else have this happen to them and everything be fine or what problems did you have? I just want him to be okay😞