Baby has reflux and nothing stops the crying, any suggestions?

My 4 week old has been diagnosed with reflux. I believe it is silent reflux because he shows ALL symptoms of it. He is currently taking Prevacid Salutab twice a day, which doesn't seem to be doing anything. He drinks Enfamil Gentlease formula (directed by doctor). He is still is having episodes of crying while being fed *screaming crying*. I have tried different temperatures of formula, holding him up while feeding, burping after every ounce, rocking him, switching bottles and , using a pacifier, mixing gripe water in with his formula....nothing seems to help and I feel like he is in pain all the time and I feel like it is getting worse. It makes me sad to see him like this especially when he eats. Sometimes he goes the entire day crying and sleeping for only 20 mins at a time. I also keep him up about 10 mins after feeding him and keep him at a 30 degree angle if he is laying down. Has anyone ever experienced this? What has helped? Could the prevacid be making it worse?