Hello mommies, any advice on how to start breastfeeding again? My baby is 9 weeks old and I quit…

Hello mommies, any advice on how to start breastfeeding again? My baby is 9 weeks old and I quit breastfeeding when he was four weeks old, I'm a little dried up, how can I build up my milk supply? He's having bad GI/digestion issues due to the formula