Sweet taste on waking

Hi! I was diagnosed with Persistent Vertiginous Migraine just over 2 years ago and am on 25mg amitriptyline but my body has become tolerant to it (I’m speaking my GP tomorrow)
So, along with my previous symptoms creeping back, I am noticing that my mouth/saliva tastes very sweet in the morning. I’ve been wondering about it and it just occurred to me that it might be another, new to me, symptom of the migraine.
Has anyone else come across this, please?
Thank you!