For the past few months i have been waking up with feelings of panic/choking while spitting up saliva. this happens a few times per week. what could be causing these symptoms ?

Depending on your sleep position, you may be accumulating saliva at the back of your throat which causes you to cough/choke and wakes you up. Are you taking any meds or other substances that reduce your swallowing reflex or increase saliva production? Do you have any out of the ordinary problems with your mouth or tongue such as infections, tooth decay or masses? Might be useful to see your Dr.

Although NOT feasible to provide an accurate answer based on your post, might ponder the presence of postnasal drip from sinuses or gastroesophageal reflux disease. See your doctor and have this fully evaluated.