Weight gain @ 22 weeks

Hi all! I will be 22 weeks on Thursday and becoming slightly concerned about my weight. Wanted to see if anyone else out there had similarities and a healthy weight baby. My pre pregnancy weight was 112 and I'm 5'7. I'm now about 117-118lbs. What kills me is everyone says they can't really tell I'm pregnant. At my 20 week ultrasound they told me baby was in the 12 percentile for weight 😳....I work in the same dr. Office as my ob and she said everything looked perfect. I have an appointment next week with her and will ask her then about the 12 percentile for baby but has or is anyone packing on the weight slowly like me? Hoping for some encouragement! Thanks mommies 💙💗