Mommy, the baby is in his third week today. He's been very fussy. He cries…

Mommy, the baby is in his third week today. He's been very fussy. He cries and pulls at his legs (as if he has tummy pain). Very capricious, doesn't eat and sleeps poorly. Temperature 37.2. Is this colic? ?? The internet says 37.2 is normal for a child. We give him bio-yogurt. And now we tried some dill water. He's sleeping. What should we do?