Small percentile

So at 28 weeks they measured my stomach and said I was measuring small so I went for an ultrasound and she was doing fine just measuring in the 40th percentile. She wasn’t worried and then going to my 32 weeks appointment I was measuring small so she wanted to do another ultrasound. It got pushed back due to weather to 33 weeks 1 day today. Apparently baby is now in the 20th percentile and small which is now stressing me out she isn’t growing like she needs to. So they have me coming in for a non stress test Thursday and another ultrasound next week and also another appointment to measure fluids... all of this has me super worried... anyone gone through something similar? I just know they get concerned when baby is lower then the 10th percentile and now that she is in the 20th it has me freaking out... nothing is ever easy!! My blood pressure has been fine every appointment, my weight gain has been normal just baby is small... oh and also she has me doing more kick counts daily. Any stories or advice? ?