9mo old refusing formula

Ashley • Happily married, have a wonderful son, and a sweet baby girl 💜

My son is 9mo old and has been on formula since 3mo. Starting this past weekend he all of a sudden will not drink more than 2oz (sometimes only 0.5oz) at a time and normally takes 3-4 hours before even allowing me to give him more--he turns his head, shuts his mouth, and shakes his head "no" when he's done. He's not dehydrated (still has tears when cries, at least 3-4 wet diapers), but he's not eating enough solids to justify the decrease in formula. It's not the formula itself as he went to day care yesterday and had 3 bottles of 5oz (same formula), but as soon as he got home he refused it when I tried feeding him at night. I'm at my wits end since he eats 25-30oz during the week (mainly due to day care) but I can barely get him to eat 15-20oz on the weekend. Any advice??