LO not eating as much suddenly

Julie

LO 5 weeks and 5 days. She was eating 3 ounces every 2-3 hours up until yesterday. Sometimes it seemed like she was even hungry after 3’ounces. Now she won’t eat more than 1-1.5 ounces every couple hours. She’s sleeping shorter lengths of time (up every 1.5 hours all night and only napping 5-30 minutes). Up until now she was napping up to 2 hours and 4 hour stretches at night. Is this normal? Wondering if she’s sick.