Ok so my 4 month old has always fallen asleep while nursing, and was already sleeping through the night, a few days ago he started waking up every hour (or half hour!) So my pediatrician said I should start sleep training. I've only tried a couple of days but he won't stop crying unless he nurses, he would cry so much he runs out of air and coughs and cries uncontrollably. I've tried comforting without picking him up, picking him up to calm him down, letting him cry for a long period (like 15minutes) and nothing seems to calm him down. Please any advise, suggestions, any help at all would be appreciated!!