I woke up with post nasal drip! It feels like I swallowed knives. Any at home remedies to soothe it? Could it turn into something more?

Possible allergies. See if there is sneezing, watery eyes, runny nose. If so, then you are allergic to something. Take claritin. If there is nasal congestion, then Claritin d instead (if no other medical problems) the post nasal drip is mucous draining down the back of throat during the night which probably dries up and gives you that sensation. If the mucus builds up, you may develop a cough or bronchitis.