Formula needs

So we are new to the whole formula world. We are still in the process of transitioning and are currently at 4 formula feeds and one nursing feed a day. Typically, my guy eats between 28-32 oz formula (no idea if that’s normal or not). But today I STRUGGLED to get 24 oz into him. When I picked him up from daycare, he had only had 8.5oz. So when I got him home and tried to feed him his normal 6oz bottle, he only drank 4oz and refused. I’m not sure what is going on, if I should be worried or call the pediatrician. Thoughts?!