Measuring behind

I had a follow up appointment today, 2 weeks ago at my 22 week ultrasound my baby girl was only measuring at the 25th percentile. I already had diabetes prior to being pregnant so they started me on insulin early, but my A1c and sugars have been fine not too high. My dr advised he no longer feels comfortable and is moving me to higher risk doctors. I’m trying not to freak out. Has anyone else measured this behind and been okay? First time mom and already worried because of my health even though I’ve done everything i can to improve it. I’m terrified of a miscarriage especially because I’ve been starting to swell and my blood pressure was high today