help

my baby is 3 and half months old . I have on the dr brown bottles and the c & g first formula. from first day my baby has had bad wind and bad hicupps.. my doc said it was reflux so was put on gaviscon for few weeks which made no difference . so she thought it may be colic so was put on infacol again this has made no difference in 5 weeks  . she was then put on lactease drops again it hasn't worked.. she screams in agony trying to go for a poo and might only have 1 every few days . even 2-3 hours after a feed my baby will throw up and scream in agony trying to wind and fart. has anyone any advice to help as im a first time mam and getting very frustrated . iv brought her doctors and hospital loads of times . I think they are thinking its just me as this stage but I know there is something im doing wrong.