FTM! Sooo concerned!!

So I know it's normal to be worried about your baby & all ..let's say I'm like over the top w/ it. I really feel like my son isn't as big as he should be. I'm 24 &6 days. He moves a lot so im not too worried about that but I really can't get it off my mind that I don't know at what rate he's growing. I have no clue when my next ultrasound is, just a regular scheduled appt in 2 weeks for my glucose test. I feel horribleeee not knowing & will feel even worse if I go in at 30 weeks for a US & they tell me he's not growing right. I can't even go back to sleep right now on my day off because this is all im thinking about 😞