ASAP HELP! My 3mo is acting paranoid

The strangest thing but my normal playful puppy all of a sudden is acting super weird with minor grunting and keeps looking EVERY direction like if he’s scared of something or paranoid and I’m wondering if he ate something harmful or toxic and he’s just acting super weird. He took a treat but doesn’t want to eat and this is unlike him.

SHOULD I TAKE HIM INTO A VET?