mp - Don't read too much into other people's experiences here. Your journey will be completely unique - unlike anyone else. Some of us really fought with the throat goo, but many didn't.
The amazing secretions of head, mouth and throat are all water based, all of them are defense mechanisms, and all of them dehydrate the body. The secretions will thin and then cease as the healing gets under way - but are really needed until then. All those tissues are really damaged from tx. The secretions protect them, and would, ordinarily by fairly thin and non-problematic (think - runny nose). But the tx steals fluids everywhere in the body - leaving little to help thin the goop.
You MUST get the fluid loss stopped. Don't let the docs put you off about it - get the right drug to stop the vomiting. Keep asking until you get it. Then, pour in the fluids - many say 2 liters per day.
mp, keep us in touch with how you are doing. Keep reading here, but remember, your treatment experience will be unique. Be strong. Tom J