As I understand it after having gone through it, "colic" is what they call it when you've tried to eliminate everything else and the baby still cries. Right about two months our baby started doing that, particularly in the evenings, sometimes alllll evening. And she did do it for about three months. If you change formula, you have to give it a couple days for baby to get over the adjustment; have you tried one of those that is supposed to be more easily digestible?
I assume you're not breastfeeding at all? Because I was at that point and it turned out my baby was both allergic to milk proteins (still drinks soy) and also had sensitivities to some other stuff. Anyway. You just have to keep track for a while and see if there's anything that seems to make it worse.
Gas drops totally saved our bacon. Also the massage and bicycling technique someone else mentioned. After a while we could tell a 'gas cry' because she would calm down for a few min and then out of the blue just scream again as the bubbles moved around in her tummy, and then after a long while she'd finally pass it.
But also, in the evenings she'd just scream. All the colic stuff about overstimulation totally seemed to come into play for her. Nap schedule was CRUCIAL, also limiting TV exposure and finding music she liked. (Turned out to be Yo-Yo-Ma cello!) Lots of holding, lots of humming, lots of rocking....
Good luck! Send me a private message if you want to chat about it more.