The hypersalivation happened to me out of the blue last year that lasted at the most 3 - 4 months. Never found out the cause. But about two or three months after it cleared I was diagnosed with presbyesophagus (hypomotility esophageal dysphagia). I was put on 30 mg of amitriptyline but really take 20. Specialist said it's due to aging (I'm 63). I too got anxious from hypersalivation. It felt like I was drowning. Before the salivation issue I woke up and my chin was quivering. It happened again in shower a day or two later before the salivation started. Do you have GERD?