I can't let my baby cry her self to sleep coz she cries so hard she can hardly breath, what shall i do in such a case, shall i still leave her cry hard?

See her pediatrician: Take along a video of an episode. If she has no congenital heart or lung disease, have a set bedtime & routine: read, rock, wipe out her mouth after her last feed, then put her on her back in her crib in her own room, drowsy, but awake to learn to self-calm for sleep. Doing this between 1-4 mos. Helps her consolidate sleep & avoids " trained night crying" at 6 months & older.