HELP!: my baby is drooling excessively , and when sleeping or laying down will have post nasal drip and lots of mucus collecting in throat . He can't breath and starts gagging and throws up the mucus and cries uncontrollably . I have him on my bed elevated right now with a humidifier in the bedroom. I don't know what to do hes never had this happen. Is he teething or sick!? How can I help him with the mucus clogging his throat??!