fussy baby...will only go to sleep when nursing...digestion issues...help!

Blanca

my baby is 3 1/2 weeks old...her digestion was excellent up until last week...starting on thirsday her bowel movements went from one every time she fed to one or two per day...she is both breastfeeding and supplementing with formula (she was on the blue cap similac)...well i noticed she was struggling to pass gas and have bowel movements because her face gets really red when she tries to push and she cries hysterically...she only stops crying and goes to sleep when she breastfeeds...i have tried rocking her, giving her mylicon, using a pacifier, and nothing works...she stays up way longer than what a newborn is expected to abd i can tell shes sleepy she just cant sleep because of the discomfort she feels...her cry is certainly different...even when she is sleeping she moves a lot and makes noises...before she was able to pass gas and even have bowel movements in her sleep..she would raise her little legs...now she tries to do the same but nothing happens...she does have at least one bowel movement a day though and its huge...i can see the relief on her face after she has it...so i called the dr and they said she wouldnt be considered to have constipation because she at least has one bowel movement but it hurts me to see her in pain...i have also tried massaging her tummy and doing bicycle exercises with her legs...what should i do??

my husband is getting some gripe water right now to try it, but im running out of options...she was up for about three hrs right now and will only stay asleep in my arms...is this colic?? do all babies make a lot of noises when sleeping? oh and we also switched her formula to the similac pro sensitive yesterday...like i said she only supplements with formula so she might have anywhere from 4-8 oz a day of formula...now im thinking that my breast milk is making her sick...i cry when i hear her cry because i. dont know what to do...right now as her tummy is making all sorts of noises, she begins grunting in her sleep...