Is baby growing correctly?

ShaKerra • Mom to a 6yr old Princess... trying for another Princess.
I'm 28 weeks exactly as of today. Most apps say baby should be about 2 pounds but I'm worried that she may not be. I've always been small but I just thought that entering my 3rd trimester, I should be much bigger. Will I gain anymore weight? How can I find out if my baby is really growing on schedule?