Sleeping during nursing

My son was bottle feed since he's born due to low production of breast milk. We tried to increase lactation by many things, but we know that no latching then no milk can happen. So we also kept trying breast feeding. Though breast milk production increased by a very small amount, breast feeding is almost impossible when he's sleeping. And he sleeps within every 2/3 minutes talking the breast nipple in his mouth. Also formula milk seemed not suiting him, he were fussy and gassy along with mucus in him poop, we changed and changed among formula milk. Nothing seemed working. So we tried exclusively breast feeding when my son is 2 months old.

Then things got worse, he don't even wake up within 5-7 hours for hunger. We tried breast pump, we tried latching but due to insufficient breastfeeding Milk is not producing that much baby needs. what do we do now?