3 months old weight slowed down

Is it normal for 3 months old slowed down in gaining weight? His weight has been the same for 3-4 weeks. Previously he was gaining weight quite fast. Now is 5.85kg at 3 months old. Feeding FM 120ml, every 3hrs, sleeping through the night. No feeding issue. Did not lose any weight so far. Is it normal? He weighs 3.08kg at birth At what rate should baby be gaining weight ? Is it like every 2-3 weeks or so. And from the app it shows baby should be at least 6kg