gain weigth

Hi mga momshies, 20 weeks pregnant po ako now. May last month prenatal check up is nasa 52 kg ako and then kahapon nasa 58 kg na po. My ob was surprised about it bat lumaki daw aq ng ganon. I asked her kung bakit sabi nya we will observe lang daw sa next check up ko. Nagtaka lang rin ako, normal lang ba ung na gain kong weight mga momsh?