If weight is 5 kg at age of 10 wk then its appropriate for age, just measure length and head circumference by pediatrician, and do growth monitoring, and it will be charted on growth chart then can tell how baby is growing, no need to panic if baby well developmentally, active, achieving milestones as per age,
Next Steps
Growth monitoring in every vaccination visit or 3 monthly
Health Tips
At 6 months baby weight should be 6 kg so no worries