My son cries in the evening...?

My son is 2 months old. From 6-11 at night - he is terrible. He cries nonstop even when being held. He clenches his fists and jolts his legs out. I know he has bad gas. He has one supplemental formula feeding a day(all else is bmilk) - for this we switched from nestle good start to soy formula bc it was worse. We use gas drops... gripe water and colic calm, burp well, feed upright & he takes baby zantac for reflux. He doesn't eat well during this time and has a terrible shreiking cry... We do all we can do but ultimately he exhausts himself during this time and then sleeps fairly well during the night. It stresses me out though and I'd love to know what is going on.....wish I could help him feel better. Anyone have this with their baby? How long did it take to get better? Any advice?