Baby not content

Sage

My LO is 3 weeks old and seems to never be content. He fusses whenever he’s awake pretty much. He could be fed changed and even being held but not happy! We’ve tried gas drops and gripe water and he’s current drinking Similac Pro-Advance. How can i know if it’s a response to formula, allergies to dog or Colic? Or is this normal for a baby his age? I’m a first time mom and feeling very defeated.