7 weeks/eating amounts

Breanna • BeansMamA2018

My baby will be 7 weeks tomorrow. He used to eat 4 ounces like a champ but recently he has cut down to two and sometimes three ounces. He ate a four ounce this morning but again is back down to two ounces or three. Is this normal or not enough for him. He still has normal poops and wet diapers. When we try to give him more he gets mad so we assume he is full after trying two or three times. We do burp often. Any ideas?