Over eating?

Anyone elses baby severely over eating? My son was ebf until he was 8 weeks old when we discovered he had failure to thrive due to a problem with my milk fat. Now hes breast and formula fed plus a small amount of pureed foods but he constantly wants to eat. Hes eating 7oz bottles every 2-4 hours plus breastfeeding in between and 2 bottles at night. Im going through 6 tins of formula a month. Iv spoken with his dr and she says shes just not sure, iv been trying to space out his feedings to slow him down but i just end up with a screaming baby.... Im getting so frustrated. Hes turning into quite the little chub