Failure to Thrive in a 3 month old

My son has recently been diagnosed with failure to thrive.  He is 3 months old and has gained 8 ounces since his 1 month appointment.  He didn't gain anything in the second month and has slowly started to go up in weight, but not fast enough.  He has been colicky (or atleast that is what they thought it was before he was considered to be failure to thrive).  He has a hard time focusing or tracking objects and also can not hold his head up very well.  The Dr.'s have been running all kinds of tests and so far cannot find any abnormalities.  They are going to be doing a brain scan in the near future and a test for cystic fibrosis.  I'm pretty worried about the whol ething.  Does anyone have any similar stories?  Is it common for babies who are colicky to be delayed with some of the developmental milestones?  I think it would be hard to learn to track objects and build muscle strength when all you do is eat, sleep and cry.  On a brighter note, his colick has been getting better.  Does anyone know how common it is for a colicky baby to not grow?  Can they burn that many calories crying?  Any stories or opinions would be appreciated!

[momskids193]

jm4, my daughter was a failure to thrive and actually lost weight from birth weight at 1 month.  She slowly gained a few ounces but was eating all the time.  At three months of age she was still barely 6 pounds.  She was tested for cystic fibrosis and it was positive.  She got started on enyzymes and other meds and the colicky got much better and she slowly started to gain weight.  She is 32 years old now and is doing okay as long as she takes her enyzmes and meds.  I hope it is not cf but if it is at least it can be treated.