Thats how I felt with Milo - I could never have the magic ability to distinguish one cry from another.

Is he crying non-stop for that amount of time, or just unsettled and crying in that period of time?

Milo used to cry and feed pretty much every evening ofr 3 or more hours.
He also got a lot of wind, so I used to hold him upright a lot.

Sorry if this is no help at all, but just wanted you to know that your situation is not uncommon.