Hey it's good.. as long as the baby is happy, smiling it's all good.. happy feeding

She has doubled her birth weight na. So weight gain good . Birth weight should be doubled by 5 months. So her weight gain is good

For that u need to maintain healthy diet...Diet tips for mother 
<a href="https://youtu.be/EV_RgFQoR48">https://youtu.be/EV_RgFQoR48</a> 
I hope this one will help u

<a href="http://app.babychakra.com/article/3001">Cope With Low Birth Weight Newborns</a>

<a href="http://app.babychakra.com/article/2623">Understanding Baby Weight Gain</a>

My baby girl is now 3mnths old. Her birth weight was 2.6 kg nd now her weight is 5 kg. Compared to 2nd month her weight gain is only 500 gm. How can her weigt be increased?