Urgent help!!

Daycare just called and my son is puking clear liquid AGAIN and won’t stop crying. He’s been like this for over a week, seemed better yesterday, and is back to it again today. He had an ear infection last week that we went to urgent care for, and he got antibiotics. Went to his pediatrician yesterday and she said everything looks great, but today he’s back at it again. I just don’t know what to do. Something is definitely wrong but we have no clue what. Do I take him to the ER? He doesn’t have a fever so I’m so lost and I feel so bad for him 😢