How do you know for sure if your baby has colic or acid reflux?

I mean I know the common sense stuff but how do you know for sure? My baby cries alot but it's not the whole crying for hours without stopping thing but still just because he doesn't cry for hours without stopping doesn't mean he doesn't have colic or acid reflux right? I know for sure my baby acts different then he did. He's fussy all the time!!! He spits up everyday and has "wet burps" alot. My doctor doesn't seems concerned but I AM. If there's anything I can do to make my baby more comfortable I want to do it! Somebody please comment!!!