Suggestions??

My son is 8 weeks old and formula fed. I know that generally the amount they consume equates to how much they sleep at night. He was doing great! 4oz every 3 hours and sleeping 6-7 hours each night. This week has been such a challenge. He is continuing the 4oz but waking every 3ish hours at night 😩. He went to the dr on Monday and weighs 10 pounds 13oz. I didn’t discuss with the dr at the time because the issue hadn’t really popped up yet. Has this happened to anyone else? Am I not feeding him enough? Thank you!!